Apparatus and method for transmitting and receiving broadcast signal

ABSTRACT

Disclosed is a method of transmitting a broadcast signal. The method includes encoding broadcast data based on a delivery protocol, line-layer processing the broadcast data, and physical-layer processing the broadcast data. Line-layer processing the broadcast data may include compressing the header of at least one IP packet when the broadcast data comprises the IP packet and encapsulating the IP packet into link layer packets.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 ofInternational Application No. PCT/KR2016/002411, filed on Mar. 10, 2016,which claims the benefit of U.S. Provisional Application No. 62/131,818,filed on Mar. 11, 2015 and 62/135,696, filed on Mar. 19, 2015, thecontents of which are all hereby incorporated by reference herein intheir entirety.

TECHNICAL FIELD

The present invention relates to an apparatus for transmitting abroadcast signal, an apparatus for receiving a broadcast signal, amethod of transmitting a broadcast signal and a method of receiving abroadcast signal.

BACKGROUND ART

As analog broadcast signal transmission comes to the end, varioustechnologies for transmitting/receiving digital broadcast signals arebeing developed. A digital broadcast signal may include a larger amountof video/audio data than an analog broadcast signal and further includevarious types of additional data in addition to the video/audio data.

DISCLOSURE Technical Problem

A digital broadcast system can provide high definition (HD) images,multichannel audio and various additional services. However, for digitalbroadcast, data transmission efficiency for the transmission of a largeamount of data, the robustness of transmission/reception networks andnetwork flexibility in consideration of mobile reception equipment needto be improved.

Technical Solution

There are proposed a method of transmitting a broadcast signal and anapparatus for transmitting a broadcast signal according to embodimentsof the present invention.

A method of transmitting a broadcast signal according to an embodimentof the present invention includes encoding broadcast data based on adelivery protocol, line-layer processing the broadcast data, andphysical-layer processing the broadcast data. The link-layer processingthe broadcast data may include compressing the header of at least one IPpacket when the broadcast data includes the IP packet and encapsulatingthe IP packet into link layer packets.

In the method of transmitting a broadcast signal according to anembodiment of the present invention, the the IP packet header mayinclude an RoHC processing step of reducing the size of each packetbased on a robust header compression (RoHC) scheme and an adaptationprocessing step of extracting context information from theRoHC-processed packets.

Furthermore, in the method of transmitting a broadcast signal accordingto an embodiment of the present invention, the context information maybe transmitted as link layer signaling information.

Furthermore, in the method of transmitting a broadcast signal accordingto an embodiment of the present invention, the RoHC-processed IP packetmay include a first packet including a static chain and a dynamic chain,a second packet including the dynamic chain, and a compressed thirdpacket. The static chain may include static subheader information. Thedynamic chain may include dynamic subheader information.

Furthermore, in the method of transmitting a broadcast signal accordingto an embodiment of the present invention, the adaptation processingstep may include converting the first packet into the third packet byextracting the static chain and the dynamic chain from the first packetand converting the second packet into the third packet by extracting thedynamic chain from the second packet. The context information mayinclude at least one of the extracted static chain information and theextracted dynamic chain information.

Furthermore, in the method of transmitting a broadcast signal accordingto an embodiment of the present invention, the adaptation processingstep may include converting the first packet into the second packet byextracting the static chain from the first packet. The contextinformation may include the extracted static chain information.

Furthermore, in the method of transmitting a broadcast signal accordingto an embodiment of the present invention, the first packet maycorrespond to an initiation and refresh state (IR) packet, and thesecond packet may correspond to a co-repair packet.

An apparatus for transmitting a broadcast signal according to anembodiment of the present invention includes a broadcast data encoderconfigured to encode broadcast data based on a delivery protocol, a linklayer processor configured to line-layer process the broadcast data, anda physical layer processor configured to physical-layer process thebroadcast data. The link layer processor may include an IP packet headercompression unit configured to compress the header of at least one IPpacket when the broadcast data includes the IP packet and anencapsulation unit configured to encapsulate the IP packet into linklayer packets.

Furthermore, in the apparatus for transmitting a broadcast signalaccording to an embodiment of the present invention, the IP packetheader compression unit may include an RoHC unit configured to reducethe size of each packet based on a robust header compression (RoHC)scheme and an adaptation unit configured to extract context informationfrom the RoHC-processed packets.

Furthermore, in the apparatus for transmitting a broadcast signalaccording to an embodiment of the present invention, the contextinformation may be transmitted as link layer signaling information.

Furthermore, in the apparatus for transmitting a broadcast signalaccording to an embodiment of the present invention, the RoHC-processedIP packet may include a first packet including a static chain and adynamic chain, a second packet including the dynamic chain, and acompressed third packet. The static chain may include static subheaderinformation. The dynamic chain may include dynamic subheaderinformation.

Furthermore, in the apparatus for transmitting a broadcast signalaccording to an embodiment of the present invention, the adaptation unitmay convert the first packet into the third packet by extracting thestatic chain and the dynamic chain from the first packet and convert thesecond packet into the third packet by extracting the dynamic chain fromthe second packet. The context information may include at least one ofthe extracted static chain information and the extracted dynamic chaininformation.

Furthermore, in the apparatus for transmitting a broadcast signalaccording to an embodiment of the present invention, the adaptation unitmay convert the first packet into the second packet by extracting thestatic chain from the first packet, and the context information mayinclude the extracted static chain information.

Furthermore, in the apparatus for transmitting a broadcast signalaccording to an embodiment of the present invention, the first packetmay correspond to an initiation and refresh state (IR) packet, and thesecond packet may correspond to a co-repair packet.

Advantageous Effects

The present invention can control quality of service (QoS) with respectto services or service components by processing data on the basis ofservice characteristics, thereby providing various broadcast services.

The present invention can achieve transmission flexibility bytransmitting various broadcast services through the same radio frequency(RF) signal bandwidth.

The present invention can provide methods and apparatuses fortransmitting and receiving broadcast signals, which enable digitalbroadcast signals to be received without error even when a mobilereception device is used or even in an indoor environment.

The present invention can effectively support future broadcast servicesin an environment supporting future hybrid broadcasting usingterrestrial broadcast networks and the Internet.

Hereinafter, additional effects of the present invention will bedescribed along with the configuration of the present invention.

DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a receiver protocol stack according to an embodimentof the present invention;

FIG. 2 illustrates a relation between an SLT and service layer signaling(SLS) according to an embodiment of the present invention;

FIG. 3 illustrates an SLT according to an embodiment of the presentinvention;

FIG. 4 illustrates SLS bootstrapping and a service discovery processaccording to an embodiment of the present invention;

FIG. 5 illustrates a USBD fragment for ROUTE/DASH according to anembodiment of the present invention;

FIG. 6 illustrates an S-TSID fragment for ROUTE/DASH according to anembodiment of the present invention;

FIG. 7 illustrates a USBD/USD fragment for MMT according to anembodiment of the present invention;

FIG. 8 illustrates a link layer protocol architecture according to anembodiment of the present invention;

FIG. 9 illustrates a structure of a base header of a link layer packetaccording to an embodiment of the present invention;

FIG. 10 illustrates a structure of an additional header of a link layerpacket according to an embodiment of the present invention;

FIG. 11 illustrates a structure of an additional header of a link layerpacket according to another embodiment of the present invention;

FIG. 12 illustrates a header structure of a link layer packet for anMPEG-2 TS packet and an encapsulation process thereof according to anembodiment of the present invention;

FIG. 13 illustrates an example of adaptation modes in IP headercompression according to an embodiment of the present invention(transmitting side);

FIG. 14 illustrates a link mapping table (LMT) and an RoHC-U descriptiontable according to an embodiment of the present invention;

FIG. 15 illustrates a structure of a link layer on a transmitter sideaccording to an embodiment of the present invention;

FIG. 16 illustrates a structure of a link layer on a receiver sideaccording to an embodiment of the present invention;

FIG. 17 illustrates a configuration of signaling transmission through alink layer according to an embodiment of the present invention(transmitting/receiving sides);

FIG. 18 is a block diagram illustrating a configuration of a broadcastsignal transmission apparatus for future broadcast services according toan embodiment of the present invention;

FIG. 19 is a block diagram illustrating a bit interleaved coding &modulation (BICM) block according to an embodiment of the presentinvention;

FIG. 20 is a block diagram illustrating a BICM block according toanother embodiment of the present invention;

FIG. 21 illustrates a bit interleaving process of physical layersignaling (PLS) according to an embodiment of the present invention;

FIG. 22 is a block diagram illustrating a configuration of a broadcastsignal reception apparatus for future broadcast services according to anembodiment of the present invention;

FIG. 23 illustrates a signaling hierarchy structure of a frame accordingto an embodiment of the present invention;

FIG. 24 is a table illustrating PLS1 data according to an embodiment ofthe present invention;

FIG. 25 is a table illustrating PLS2 data according to an embodiment ofthe present invention;

FIG. 26 is a table illustrating PLS2 data according to anotherembodiment of the present invention;

FIG. 27 illustrates a logical structure of a frame according to anembodiment of the present invention;

FIG. 28 illustrates PLS mapping according to an embodiment of thepresent invention;

FIG. 29 illustrates time interleaving according to an embodiment of thepresent invention;

FIG. 30 illustrates a basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention;

FIG. 31 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention;

FIG. 32 is a block diagram illustrating an interleaving addressgenerator including a main pseudo-random binary sequence (PRBS)generator and a sub-PRBS generator according to each FFT mode accordingto an embodiment of the present invention;

FIG. 33 illustrates a main PRBS used for all FFT modes according to anembodiment of the present invention;

FIG. 34 illustrates a sub-PRBS used for FFT modes and an interleavingaddress for frequency interleaving according to an embodiment of thepresent invention;

FIG. 35 illustrates a write operation of a time interleaver according toan embodiment of the present invention;

FIG. 36 is a table illustrating an interleaving type applied accordingto the number of PLPs;

FIG. 37 is a block diagram including a first example of a structure of ahybrid time interleaver;

FIG. 38 is a block diagram including a second example of the structureof the hybrid time interleaver;

FIG. 39 is a block diagram including a first example of a structure of ahybrid time deinterleaver;

FIG. 40 is a block diagram including a second example of the structureof the hybrid time deinterleaver;

FIG. 41 is a view showing a protocol stack for a next generationbroadcasting system according to an embodiment of the present invention.

FIG. 42 is a conceptual diagram illustrating an interface of a linklayer according to an embodiment of the present invention.

FIG. 43 illustrates an operation in a normal mode corresponding to oneof operation modes of a link layer according to an embodiment of thepresent invention.

FIG. 44 illustrates an operation in a transparent mode corresponding toone of operation modes of a link layer according to an embodiment of thepresent invention.

FIG. 45 illustrates a configuration of a link layer at a transmitteraccording to an embodiment of the present invention (normal mode).

FIG. 46 illustrates a configuration of a link layer at a receiveraccording to an embodiment of the present invention (normal mode).

FIG. 47 is a diagram illustrating definition according to link layerorganization type according to an embodiment of the present invention.

FIG. 48 is a diagram illustrating processing of a broadcast signal whena logical data path includes only a normal data pipe according to anembodiment of the present invention.

FIG. 49 is a diagram illustrating processing of a broadcast signal whena logical data path includes a normal data pipe and a base data pipeaccording to an embodiment of the present invention.

FIG. 50 is a diagram illustrating processing of a broadcast signal whena logical data path includes a normal data pipe and a dedicated channelaccording to an embodiment of the present invention.

FIG. 51 is a diagram illustrating processing of a broadcast signal whena logical data path includes a normal data pipe, a base data pipe, and adedicated channel according to an embodiment of the present invention.

FIG. 52 is a diagram illustrating a detailed processing operation of asignal and/or data in a link layer of a receiver when a logical datapath includes a normal data pipe, a base data pipe, and a dedicatedchannel according to an embodiment of the present invention.

FIG. 53 is a diagram illustrating syntax of a fast information channel(FIC) according to an embodiment of the present invention.

FIG. 54 is a diagram illustrating syntax of an emergency alert table(EAT) according to an embodiment of the present invention.

FIG. 55 is a diagram illustrating a packet transmitted to a data pipeaccording to an embodiment of the present invention.

FIG. 56 is a diagram illustrating a detailed processing operation of asignal and/or data in each protocol stack of a transmitter when alogical data path of a physical layer includes a dedicated channel, abase DP, and a normal data DP, according to another embodiment of thepresent invention.

FIG. 57 is a diagram illustrating a detailed processing operation of asignal and/or data in each protocol stack of a receiver when a logicaldata path of a physical layer includes a dedicated channel, a base DP,and a normal data DP, according to another embodiment of the presentinvention.

FIG. 58 is a diagram illustrating the syntax of an FIC according toanother embodiment of the present invention.

FIG. 59 is a diagram illustrating signaling_Information_Part( )according to an embodiment of the present invention.

FIG. 60 is a diagram illustrating a procedure for controlling anoperation mode of a transmitter and/or a receiver in a link layeraccording to an embodiment of the present invention.

FIG. 61 is a diagram illustrating an operation in a link layer accordingto a value of a flag and a type of a packet transmitted to a physicallayer according to an embodiment of the present invention.

FIG. 62 is a diagram a descriptor for signaling a mode control parameteraccording to an embodiment of the present invention.

FIG. 63 is a diagram illustrating an operation of a transmitter forcontrolling a operation mode according to an embodiment of the presentinvention.

FIG. 64 is a diagram illustrating an operation of a receiver forprocessing a broadcast signal according to an operation mode accordingto an embodiment of the present invention.

FIG. 65 is a diagram illustrating information for identifying anencapsulation mode according to an embodiment of the present invention.

FIG. 66 is a diagram illustrating information for identifying a headercompression mode according to an embodiment of the present invention.

FIG. 67 is a diagram illustrating information for identifying a packetreconfiguration mode according to an embodiment of the presentinvention.

FIG. 68 is a diagram illustrating a context transmission mode accordingto an embodiment of the present invention.

FIG. 69 is a diagram illustrating initialization information when RoHCis applied by a header compression scheme according to an embodiment ofthe present invention.

FIG. 70 is a diagram illustrating information for identifying link layersignaling path configuration according to an embodiment of the presentinvention.

FIG. 71 is a diagram illustrating information about signaling pathconfiguration by a bit mapping scheme according to an embodiment of thepresent invention.

FIG. 72 is a flowchart illustrating a link layer initializationprocedure according to an embodiment of the present invention.

FIG. 73 is a flowchart illustrating a link layer initializationprocedure according to another embodiment of the present invention.

FIG. 74 is a diagram illustrating a signaling format for transmitting aninitialization parameter according to an embodiment of the presentinvention.

FIG. 75 is a diagram illustrating a signaling format for transmitting aninitialization parameter according to another embodiment of the presentinvention.

FIG. 76 is a diagram illustrating a signaling format for transmitting aninitialization parameter according to another embodiment of the presentinvention.

FIG. 77 is a diagram illustrating a receiver according to an embodimentof the present invention.

FIG. 78 is a diagram illustrating a layer structure when a dedicatedchannel is present according to an embodiment of the present invention.

FIG. 79 is a diagram illustrating a layer structure when a dedicatedchannel is present according to another embodiment of the presentinvention.

FIG. 80 is a diagram illustrating a layer structure when a dedicatedchannel is independently present according to an embodiment of thepresent invention.

FIG. 81 is a diagram illustrating a layer structure when a dedicatedchannel is independently present according to another embodiment of thepresent invention.

FIG. 82 is a diagram illustrating a layer structure when a dedicatedchannel transmits specific data according to an embodiment of thepresent invention.

FIG. 83 is a diagram illustrating a format of (or a dedicated format) ofdata transmitted through a dedicated channel according to an embodimentof the present invention.

FIG. 84 is a diagram illustrating configuration information of adedicated channel for signaling information about a dedicated channelaccording to an embodiment of the present invention.

FIG. 85 shows a transmitter-side link layer structure and a method oftransmitting signaling information according to an embodiment of thepresent invention.

FIG. 86 shows a receiver-side link layer structure and a method ofreceiving signaling information according to an embodiment of thepresent invention.

FIG. 87 shows the transmission path of signaling information accordingto an embodiment of the present invention.

FIG. 88 shows the transmission path of an FIT according to an embodimentof the present invention.

FIG. 89 shows the syntax of an FIT according to an embodiment of thepresent invention.

FIG. 90 shows FIT information according to an embodiment of the presentinvention.

FIG. 91 shows service category information according to an embodiment ofthe present invention.

FIG. 92 shows a broadcast signaling location descriptor according to anembodiment of the present invention.

FIG. 93 is a view showing the structure of a Robust Header Compression(RoHC) packet and an uncompressed Internet Protocol (IP) packetaccording to an embodiment of the present invention.

FIG. 94 is a view showing a concept of an RoHC packet stream accordingto an embodiment of the present invention.

FIG. 95 is a view showing a context information propagation procedureduring transport of an RoHC packet stream according to an embodiment ofthe present invention.

FIG. 96 is a view showing a transmitting and receiving system of an IPstream, to which an IP header compression scheme according to anembodiment of the present invention is applied.

FIG. 97 is a view showing an IP overhead reduction procedure in atransmitter/receiver according to an embodiment of the presentinvention.

FIG. 98 is a view showing a procedure of reconfiguring an RoHC packet toconfigure a new packet stream according to an embodiment of the presentinvention.

FIG. 99 is a view showing a procedure of converting an IR packet into ageneral header compressed packet in a procedure of reconfiguring an RoHCpacket to configure a new packet stream according to an embodiment ofthe present invention.

FIG. 100 is a view showing a procedure of converting an IR-DYN packetinto a general header compressed packet in a procedure of reconfiguringan RoHC packet to configure a new packet stream according to anembodiment of the present invention.

FIG. 101 is a view showing a procedure of converting an IR packet intoan IR-DYN packet in a procedure of reconfiguring an RoHC packet toconfigure a new packet stream according to an embodiment of the presentinvention.

FIG. 102 is a view showing a configuration and recovery procedure of anRoHC packet stream in a first configuration mode (Configuration Mode #1)according to an embodiment of the present invention.

FIG. 103 is a view showing a configuration and recovery procedure of anRoHC packet stream in a second configuration mode (Configuration Mode#2) according to an embodiment of the present invention.

FIG. 104 is a view showing a configuration and recovery procedure of anRoHC packet stream in a third configuration mode (Configuration Mode #3)according to an embodiment of the present invention.

FIG. 105 is a view showing a combination of information that can bedelivered through Out of Band according to an embodiment of the presentinvention.

FIG. 106 is a view showing configuration of a descriptor including astatic chain according to an embodiment of the present invention.

FIG. 107 is a view showing configuration of a descriptor including adynamic chain according to an embodiment of the present invention.

FIG. 108 is a view showing configuration of a packet format including astatic chain and a packet format including a dynamic chain according toan embodiment of the present invention.

FIG. 109 is a diagram illustrating configuration ofROHC_init_descriptor( ) according to an embodiment of the presentinvention.

FIG. 110 is a diagram illustrating configuration ofFast_Information_Chunk( ) including ROHC_init_descriptor( ) according toan embodiment of the present invention.

FIG. 111 is a diagram illustrating configuration ofFast_Information_Chunk( ) including a parameter required for a RoHCinitial procedure according to an embodiment of the present invention.

FIG. 112 is a diagram illustrating configuration ofFast_Information_Chunk( ) including ROHC_init_descriptor( ) according toanother embodiment of the present invention.

FIG. 113 is a diagram illustrating configuration ofFast_Information_Chunk( ) including a parameter required for a RoHCinitial procedure according to another embodiment of the presentinvention.

FIG. 114 illustrates a configuration of a header of a packet forsignaling according to an embodiment of the present invention

FIG. 115 is a chart that defines the signaling class field according tothe present embodiment.

FIG. 116 is a chart that defines an information type.

FIG. 117 is a diagram illustrating a structure ofPayload_for_Initialization( ) according to an embodiment of the presentinvention when an information type for header compression has a value of“000.”

FIG. 118 is a diagram illustrating a structure ofPayload_for_ROHC_configuration( ) when the information type for headercompression has a value of “001.”

FIG. 119 is a diagram illustrating a structure ofPayload_for_static_chain( ) when the information type for headercompression has a value of “010.”

FIG. 120 is a diagram illustrating a structure ofPayload_for_dynamic_chain( ) when the information type for headercompression has a value of “011.”

FIG. 121 shows the header format of an IR packet of an RoHCv2 profileaccording to an embodiment of the present invention.

FIG. 122 shows the header format of a CO-repair packet of the RoHCv2profile according to an embodiment of the present invention.

FIG. 123 shows a compressed header format of the RoHCv2 profileaccording to an embodiment of the present invention.

FIG. 124 shows a method of generating a new packet stream byreconfiguring an RoHC packet according to an embodiment of the presentinvention.

FIG. 125 shows a process of transforming an IR packet into a generalheader-compressed packet or PT_0_crc3_Packet in the process ofconfiguring a new packet stream by reconfiguring an RoHC packetaccording to an embodiment of the present invention.

FIG. 126 is a diagram showing a process of transforming a Co_Repairpacket into a general header-compressed packet PT_0_crc3_Packet in theprocess of configuring a new packet stream by reconfiguring an RoHCpacket according to an embodiment of the present invention.

FIG. 127 is a diagram showing a process of transforming an IR packetinto a Co_Repair packet in the process of configuring a new packetstream by reconfiguring an RoHC packet according to an embodiment of thepresent invention.

FIG. 128 shows a method of transmitting a broadcast signal according toan embodiment of the present invention.

FIG. 129 shows the broadcast signal transmitter and broadcast signalreceiver of a broadcast system according to an embodiment of the presentinvention.

BEST MODE

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description, which will be given below withreference to the accompanying drawings, is intended to explain exemplaryembodiments of the present invention, rather than to show the onlyembodiments that can be implemented according to the present invention.The following detailed description includes specific details in order toprovide a thorough understanding of the present invention. However, itwill be apparent to those skilled in the art that the present inventionmay be practiced without such specific details.

Although the terms used in the present invention are selected fromgenerally known and used terms, some of the terms mentioned in thedescription of the present invention have been selected by the applicantat his or her discretion, the detailed meanings of which are describedin relevant parts of the description herein. Furthermore, it is requiredthat the present invention is understood, not simply by the actual termsused but by the meanings of each term lying within.

The present invention provides apparatuses and methods for transmittingand receiving broadcast signals for future broadcast services. Futurebroadcast services according to an embodiment of the present inventioninclude a terrestrial broadcast service, a mobile broadcast service, anultra high definition television (UHDTV) service, etc. The presentinvention may process broadcast signals for the future broadcastservices through non-MIMO (Multiple Input Multiple Output) or MIMOaccording to one embodiment. A non-MIMO scheme according to anembodiment of the present invention may include a MISO (Multiple InputSingle Output) scheme, a SISO (Single Input Single Output) scheme, etc.

FIG. 1 illustrates a receiver protocol stack according to an embodimentof the present invention.

Two schemes may be used in broadcast service delivery through abroadcast network.

In a first scheme, media processing units (MPUs) are transmitted usingan MMT protocol (MMTP) based on MPEG media transport (MMT). In a secondscheme, dynamic adaptive streaming over HTTP (DASH) segments may betransmitted using real time object delivery over unidirectionaltransport (ROUTE) based on MPEG DASH.

Non-timed content including NRT media, EPG data, and other files isdelivered with ROUTE. Signaling may be delivered over MMTP and/or ROUTE,while bootstrap signaling information is provided by the means of theService List Table (SLT).

In hybrid service delivery, MPEG DASH over HTTP/TCP/IP is used on thebroadband side. Media files in ISO Base Media File Format (BMFF) areused as the delivery, media encapsulation and synchronization format forboth broadcast and broadband delivery. Here, hybrid service delivery mayrefer to a case in which one or more program elements are deliveredthrough a broadband path.

Services are delivered using three functional layers. These are thephysical layer, the delivery layer and the service management layer. Thephysical layer provides the mechanism by which signaling, serviceannouncement and IP packet streams are transported over the broadcastphysical layer and/or broadband physical layer. The delivery layerprovides object and object flow transport functionality. It is enabledby the MMTP or the ROUTE protocol, operating on a UDP/IP multicast overthe broadcast physical layer, and enabled by the HTTP protocol on aTCP/IP unicast over the broadband physical layer. The service managementlayer enables any type of service, such as linear TV or HTML5application service, to be carried by the underlying delivery andphysical layers.

In this figure, a protocol stack part on a broadcast side may be dividedinto a part transmitted through the SLT and the MMTP, and a parttransmitted through ROUTE.

The SLT may be encapsulated through UDP and IP layers. Here, the SLTwill be described below. The MMTP may transmit data formatted in an MPUformat defined in MMT, and signaling information according to the MMTP.The data may be encapsulated through the UDP and IP layers. ROUTE maytransmit data formatted in a DASH segment form, signaling information,and non-timed data such as NRT data, etc. The data may be encapsulatedthrough the UDP and IP layers. According to a given embodiment, some orall processing according to the UDP and IP layers may be omitted. Here,the illustrated signaling information may be signaling informationrelated to a service.

The part transmitted through the SLT and the MMTP and the parttransmitted through ROUTE may be processed in the UDP and IP layers, andthen encapsulated again in a data link layer. The link layer will bedescribed below. Broadcast data processed in the link layer may bemulticast as a broadcast signal through processes such asencoding/interleaving, etc. in the physical layer.

In this figure, a protocol stack part on a broadband side may betransmitted through HTTP as described above. Data formatted in a DASHsegment form, signaling information, NRT information, etc. may betransmitted through HTTP. Here, the illustrated signaling informationmay be signaling information related to a service. The data may beprocessed through the TCP layer and the IP layer, and then encapsulatedinto the link layer. According to a given embodiment, some or all of theTCP, the IP, and the link layer may be omitted. Broadband data processedthereafter may be transmitted by unicast in the broadband through aprocess for transmission in the physical layer.

Service can be a collection of media components presented to the user inaggregate; components can be of multiple media types; a Service can beeither continuous or intermittent; a Service can be Real Time orNon-Real Time; Real Time Service can consist of a sequence of TVprograms.

FIG. 2 illustrates a relation between the SLT and SLS according to anembodiment of the present invention.

Service signaling provides service discovery and descriptioninformation, and comprises two functional components: Bootstrapsignaling via the Service List Table (SLT) and the Service LayerSignaling (SLS). These represent the information which is necessary todiscover and acquire user services. The SLT enables the receiver tobuild a basic service list, and bootstrap the discovery of the SLS foreach service.

The SLT can enable very rapid acquisition of basic service information.The SLS enables the receiver to discover and access services and theircontent components. Details of the SLT and SLS will be described below.

As described in the foregoing, the SLT may be transmitted throughUDP/IP. In this instance, according to a given embodiment, datacorresponding to the SLT may be delivered through the most robust schemein this transmission.

The SLT may have access information for accessing SLS delivered by theROUTE protocol. In other words, the SLT may be bootstrapped into SLSaccording to the ROUTE protocol. The SLS is signaling informationpositioned in an upper layer of ROUTE in the above-described protocolstack, and may be delivered through ROUTE/UDP/IP. The SLS may betransmitted through one of LCT sessions included in a ROUTE session. Itis possible to access a service component corresponding to a desiredservice using the SLS.

In addition, the SLT may have access information for accessing an MMTsignaling component delivered by MMTP. In other words, the SLT may bebootstrapped into SLS according to the MMTP. The SLS may be delivered byan MMTP signaling message defined in MMT. It is possible to access astreaming service component (MPU) corresponding to a desired serviceusing the SLS. As described in the foregoing, in the present invention,an NRT service component is delivered through the ROUTE protocol, andthe SLS according to the MMTP may include information for accessing theROUTE protocol. In broadband delivery, the SLS is carried overHTTP(S)/TCP/IP.

FIG. 3 illustrates an SLT according to an embodiment of the presentinvention.

First, a description will be given of a relation among respectivelogical entities of service management, delivery, and a physical layer.

Services may be signaled as being one of two basic types. First type isa linear audio/video or audio-only service that may have an app-basedenhancement. Second type is a service whose presentation and compositionis controlled by a downloaded application that is executed uponacquisition of the service. The latter can be called an “app-based”service.

The rules regarding presence of ROUTE/LCT sessions and/or MMTP sessionsfor carrying the content components of a service may be as follows.

For broadcast delivery of a linear service without app-basedenhancement, the service's content components can be carried by either(but not both): (1) one or more ROUTE/LCT sessions, or (2) one or moreMMTP sessions.

For broadcast delivery of a linear service with app-based enhancement,the service's content components can be carried by: (1) one or moreROUTE/LCT sessions, and (2) zero or more MMTP sessions.

In certain embodiments, use of both MMTP and ROUTE for streaming mediacomponents in the same service may not be allowed.

For broadcast delivery of an app-based service, the service's contentcomponents can be carried by one or more ROUTE/LCT sessions.

Each ROUTE session comprises one or more LCT sessions which carry as awhole, or in part, the content components that make up the service. Instreaming services delivery, an LCT session may carry an individualcomponent of a user service such as an audio, video or closed captionstream. Streaming media is formatted as DASH Segments.

Each MMTP session comprises one or more MMTP packet flows which carryMMT signaling messages or as a whole, or in part, the content component.An MMTP packet flow may carry MMT signaling messages or componentsformatted as MPUs.

For the delivery of NRT User Services or system metadata, an LCT sessioncarries file-based content items. These content files may consist ofcontinuous (time-based) or discrete (non-time-based) media components ofan NRT service, or metadata such as Service Signaling or ESG fragments.Delivery of system metadata such as service signaling or ESG fragmentsmay also be achieved through the signaling message mode of MMTP.

A broadcast stream is the abstraction for an RF channel, which isdefined in terms of a carrier frequency centered within a specifiedbandwidth. It is identified by the pair [geographic area, frequency]. Aphysical layer pipe (PLP) corresponds to a portion of the RF channel.Each PLP has certain modulation and coding parameters. It is identifiedby a PLP identifier (PLPID), which is unique within the broadcast streamit belongs to. Here, PLP can be referred to as DP (data pipe).

Each service is identified by two forms of service identifier: a compactform that is used in the SLT and is unique only within the broadcastarea; and a globally unique form that is used in the SLS and the ESG. AROUTE session is identified by a source IP address, destination IPaddress and destination port number. An LCT session (associated with theservice component(s) it carries) is identified by a transport sessionidentifier (TSI) which is unique within the scope of the parent ROUTEsession. Properties common to the LCT sessions, and certain propertiesunique to individual LCT sessions, are given in a ROUTE signalingstructure called a service-based transport session instance description(S-TSID), which is part of the service layer signaling. Each LCT sessionis carried over a single physical layer pipe. According to a givenembodiment, one LCT session may be transmitted through a plurality ofPLPs. Different LCT sessions of a ROUTE session may or may not becontained in different physical layer pipes. Here, the ROUTE session maybe delivered through a plurality of PLPs. The properties described inthe S-TSID include the TSI value and PLPID for each LCT session,descriptors for the delivery objects/files, and application layer FECparameters.

A MMTP session is identified by destination IP address and destinationport number. An MMTP packet flow (associated with the servicecomponent(s) it carries) is identified by a packet_id which is uniquewithin the scope of the parent MMTP session. Properties common to eachMMTP packet flow, and certain properties of MMTP packet flows, are givenin the SLT. Properties for each MMTP session are given by MMT signalingmessages, which may be carried within the MMTP session. Different MMTPpacket flows of a MMTP session may or may not be contained in differentphysical layer pipes. Here, the MMTP session may be delivered through aplurality of PLPs. The properties described in the MMT signalingmessages include the packet_id value and PLPID for each MMTP packetflow. Here, the MMT signaling messages may have a form defined in MMT,or have a deformed form according to embodiments to be described below.

Hereinafter, a description will be given of low level signaling (LLS).

Signaling information which is carried in the payload of IP packets witha well-known address/port dedicated to this function is referred to aslow level signaling (LLS). The IP address and the port number may bedifferently configured depending on embodiments. In one embodiment, LLScan be transported in IP packets with address 224.0.23.60 anddestination port 4937/udp. LLS may be positioned in a portion expressedby “SLT” on the above-described protocol stack. However, according to agiven embodiment, the LLS may be transmitted through a separate physicalchannel (dedicated channel) in a signal frame without being subjected toprocessing of the UDP/IP layer.

UDP/IP packets that deliver LLS data may be formatted in a form referredto as an LLS table. A first byte of each UDP/IP packet that delivers theLLS data may correspond to a start of the LLS table. The maximum lengthof any LLS table is limited by the largest IP packet that can bedelivered from the PHY layer, 65,507 bytes.

The LLS table may include an LLS table ID field that identifies a typeof the LLS table, and an LLS table version field that identifies aversion of the LLS table. According to a value indicated by the LLStable ID field, the LLS table may include the above-described SLT or arating region table (RRT). The RRT may have information about contentadvisory rating.

Hereinafter, the SLT will be described. LLS can be signaling informationwhich supports rapid channel scans and bootstrapping of serviceacquisition by the receiver, and SLT can be a table of signalinginformation which is used to build a basic service listing and providebootstrap discovery of SLS.

The function of the SLT is similar to that of the program associationtable (PAT) in MPEG-2 Systems, and the fast information channel (FIC)found in ATSC Systems. For a receiver first encountering the broadcastemission, this is the place to start. SLT supports a rapid channel scanwhich allows a receiver to build a list of all the services it canreceive, with their channel name, channel number, etc., and SLT providesbootstrap information that allows a receiver to discover the SLS foreach service. For ROUTE/DASH-delivered services, the bootstrapinformation includes the destination IP address and destination port ofthe LCT session that carries the SLS. For MMT/MPU-delivered services,the bootstrap information includes the destination IP address anddestination port of the MMTP session carrying the SLS.

The SLT supports rapid channel scans and service acquisition byincluding the following information about each service in the broadcaststream. First, the SLT can include information necessary to allow thepresentation of a service list that is meaningful to viewers and thatcan support initial service selection via channel number or up/downselection. Second, the SLT can include information necessary to locatethe service layer signaling for each service listed. That is, the SLTmay include access information related to a location at which the SLS isdelivered.

The illustrated SLT according to the present embodiment is expressed asan XML document having an SLT root element. According to a givenembodiment, the SLT may be expressed in a binary format or an XMLdocument.

The SLT root element of the SLT illustrated in the figure may include@bsid, @sltSectionVersion, @sltSectionNumber, @totalSltSectionNumbers,@language, @capabilities, InetSigLoc and/or Service. According to agiven embodiment, the SLT root element may further include @providerId.According to a given embodiment, the SLT root element may not include@language.

The service element may include @serviceId, @SLTserviceSeqNumber,@protected, @majorChannelNo, @minorChannelNo, @serviceCategory,@shortServiceName, @hidden, @slsProtocolType, BroadcastSignaling,@slsPlpId, @slsDestinationIpAddress, @slsDestinationUdpPort,@slsSourceIpAddress, @slsMajorProtocolVersion, @SlsMinorProtocolVersion,@serviceLanguage, @broadbandAccessRequired, @capabilities and/orInetSigLoc.

According to a given embodiment, an attribute or an element of the SLTmay be added/changed/deleted. Each element included in the SLT mayadditionally have a separate attribute or element, and some attribute orelements according to the present embodiment may be omitted. Here, afield which is marked with @ may correspond to an attribute, and a fieldwhich is not marked with @ may correspond to an element.

@bsid is an identifier of the whole broadcast stream. The value of BSIDmay be unique on a regional level.

@providerId can be an index of broadcaster that is using part or all ofthis broadcast stream. This is an optional attribute. When it's notpresent, it means that this broadcast stream is being used by onebroadcaster. @providerId is not illustrated in the figure.

@sltSectionVersion can be a version number of the SLT section. ThesltSectionVersion can be incremented by 1 when a change in theinformation carried within the slt occurs. When it reaches maximumvalue, it wraps around to 0.

@sltSectionNumber can be the number, counting from 1, of this section ofthe SLT. In other words, @sltSectionNumber may correspond to a sectionnumber of the SLT section. When this field is not used,@sltSectionNumber may be set to a default value of 1.

@totalSltSectionNumbers can be the total number of sections (that is,the section with the highest sltSectionNumber) of the SLT of which thissection is part. sltSectionNumber and totalSltSectionNumbers togethercan be considered to indicate “Part M of N” of one portion of the SLTwhen it is sent in fragments. In other words, when the SLT istransmitted, transmission through fragmentation may be supported. Whenthis field is not used, @totalSltSectionNumbers may be set to a defaultvalue of 1. A case in which this field is not used may correspond to acase in which the SLT is not transmitted by being fragmented.

@language can indicate primary language of the services included in thisslt instance. According to a given embodiment, a value of this field mayhave be a three-character language code defined in the ISO. This fieldmay be omitted.

@capabilities can indicate required capabilities for decoding andmeaningfully presenting the content for all the services in this sltinstance.

InetSigLoc can provide a URL telling the receiver where it can acquireany requested type of data from external server(s) via broadband. Thiselement may include @urlType as a lower field. According to a value ofthe @urlType field, a type of a URL provided by InetSigLoc may beindicated. According to a given embodiment, when the @urlType field hasa value of 0, InetSigLoc may provide a URL of a signaling server. Whenthe @urlType field has a value of 1, InetSigLoc may provide a URL of anESG server. When the @urlType field has other values, the field may bereserved for future use.

The service field is an element having information about each service,and may correspond to a service entry. Service element fieldscorresponding to the number of services indicated by the SLT may bepresent. Hereinafter, a description will be given of a lowerattribute/element of the service field.

@serviceId can be an integer number that uniquely identify this servicewithin the scope of this broadcast area. According to a givenembodiment, a scope of @serviceId may be changed. @SLTserviceSeqNumbercan be an integer number that indicates the sequence number of the SLTservice information with service ID equal to the serviceId attributeabove. SLTserviceSeqNumber value can start at 0 for each service and canbe incremented by 1 every time any attribute in this service element ischanged. If no attribute values are changed compared to the previousService element with a particular value of ServiceID thenSLTserviceSeqNumber would not be incremented. The SLTserviceSeqNumberfield wraps back to 0 after reaching the maximum value.

@protected is flag information which may indicate whether one or morecomponents for significant reproduction of the service are in aprotected state. When set to “1” (true), that one or more componentsnecessary for meaningful presentation is protected. When set to “0”(false), this flag indicates that no components necessary for meaningfulpresentation of the service are protected. Default value is false.

@majorChannelNo is an integer number representing the “major” channelnumber of the service. An example of the field may have a range of 1 to999.

@minorChannelNo is an integer number representing the “minor” channelnumber of the service. An example of the field may have a range of 1 to999.

@serviceCategory can indicate the category of this service. This fieldmay indicate a type that varies depending on embodiments. According to agiven embodiment, when this field has values of 1, 2, and 3, the valuesmay correspond to a linear A/V service, a linear audio only service, andan app-based service, respectively. When this field has a value of 0,the value may correspond to a service of an undefined category. Whenthis field has other values except for 1, 2, and 3, the field may bereserved for future use. @shortServiceName can be a short string name ofthe Service.

@hidden can be Boolean value that when present and set to “true”indicates that the service is intended for testing or proprietary use,and is not to be selected by ordinary TV receivers. The default value is“false” when not present.

@slsProtocolType can be an attribute indicating the type of protocol ofService Layer Signaling used by this service. This field may indicate atype that varies depending on embodiments. According to a givenembodiment, when this field has values of 1 and 2, protocols of SLS usedby respective corresponding services may be ROUTE and MMTP,respectively. When this field has other values except for 0, the fieldmay be reserved for future use. This field may be referred to as@slsProtocol.

BroadcastSignaling and lower attributes/elements thereof may provideinformation related to broadcast signaling. When the BroadcastSignalingelement is not present, the child element InetSigLoc of the parentservice element can be present and its attribute urlType includesURL_type 0x00 (URL to signaling server). In this case attribute urlsupports the query parameter svc=<service_id> where service_idcorresponds to the serviceId attribute for the parent service element.

Alternatively when the BroadcastSignaling element is not present, theelement InetSigLoc can be present as a child element of the slt rootelement and the attribute urlType of that InetSigLoc element includesURL_type 0x00 (URL to signaling server). In this case, attribute url forURL_type 0x00 supports the query parameter svc=<service_id> whereservice_id corresponds to the serviceId attribute for the parent Serviceelement.

@slsPlpId can be a string representing an integer number indicating thePLP ID of the physical layer pipe carrying the SLS for this service.

@slsDestinationIpAddress can be a string containing the dotted-IPv4destination address of the packets carrying SLS data for this service.

@slsDestinationUdpPort can be a string containing the port number of thepackets carrying SLS data for this service. As described in theforegoing, SLS bootstrapping may be performed by destination IP/UDPinformation.

@slsSourceIpAddress can be a string containing the dotted-IPv4 sourceaddress of the packets carrying SLS data for this service.

@slsMajorProtocolVersion can be major version number of the protocolused to deliver the service layer signaling for this service. Defaultvalue is 1.

@SlsMinorProtocolVersion can be minor version number of the protocolused to deliver the service layer signaling for this service. Defaultvalue is 0.

@serviceLanguage can be a three-character language code indicating theprimary language of the service. A value of this field may have a formthat varies depending on embodiments.

@broadbandAccessRequired can be a Boolean indicating that broadbandaccess is required for a receiver to make a meaningful presentation ofthe service. Default value is false. When this field has a value ofTrue, the receiver needs to access a broadband for significant servicereproduction, which may correspond to a case of hybrid service delivery.

@capabilities can represent required capabilities for decoding andmeaningfully presenting the content for the service with service IDequal to the service Id attribute above.

InetSigLoc can provide a URL for access to signaling or announcementinformation via broadband, if available. Its data type can be anextension of the any URL data type, adding an @urlType attribute thatindicates what the URL gives access to. An @urlType field of this fieldmay indicate the same meaning as that of the @urlType field ofInetSigLoc described above. When an InetSigLoc element of attributeURL_type 0x00 is present as an element of the SLT, it can be used tomake HTTP requests for signaling metadata. The HTTP POST message bodymay include a service term. When the InetSigLoc element appears at thesection level, the service term is used to indicate the service to whichthe requested signaling metadata objects apply. If the service term isnot present, then the signaling metadata objects for all services in thesection are requested. When the InetSigLoc appears at the service level,then no service term is needed to designate the desired service. When anInetSigLoc element of attribute URL_type 0x01 is provided, it can beused to retrieve ESG data via broadband. If the element appears as achild element of the service element, then the URL can be used toretrieve ESG data for that service. If the element appears as a childelement of the SLT element, then the URL can be used to retrieve ESGdata for all services in that section.

In another example of the SLT, @sltSectionVersion, @sltSectionNumber,@totalSltSectionNumbers and/or @language fields of the SLT may beomitted

In addition, the above-described InetSigLoc field may be replaced by@sltlnetSigUri and/or @sltlnetEsgUri field. The two fields may includethe URI of the signaling server and URI information of the ESG server,respectively. The InetSigLoc field corresponding to a lower field of theSLT and the InetSigLoc field corresponding to a lower field of theservice field may be replaced in a similar manner.

The suggested default values may vary depending on embodiments. Anillustrated “use” column relates to the respective fields. Here, “1” mayindicate that a corresponding field is an essential field, and “0 . . .1” may indicate that a corresponding field is an optional field.

FIG. 4 illustrates SLS bootstrapping and a service discovery processaccording to an embodiment of the present invention.

Hereinafter, SLS will be described.

SLS can be signaling which provides information for discovery andacquisition of services and their content components.

For ROUTE/DASH, the SLS for each service describes characteristics ofthe service, such as a list of its components and where to acquire them,and the receiver capabilities required to make a meaningful presentationof the service. In the ROUTE/DASH system, the SLS includes the userservice bundle description (USBD), the S-TSID and the DASH mediapresentation description (MPD). Here, USBD or user service description(USD) is one of SLS XML fragments, and may function as a signaling herbthat describes specific descriptive information. USBD/USD may beextended beyond 3GPP MBMS. Details of USBD/USD will be described below.

The service signaling focuses on basic attributes of the service itself,especially those attributes needed to acquire the service. Properties ofthe service and programming that are intended for viewers appear asservice announcement, or ESG data.

Having separate Service Signaling for each service permits a receiver toacquire the appropriate SLS for a service of interest without the needto parse the entire SLS carried within a broadcast stream.

For optional broadband delivery of Service Signaling, the SLT caninclude HTTP URLs where the Service Signaling files can be obtained, asdescribed above.

The LLS is used for bootstrapping SLS acquisition, and subsequently, theSLS is used to acquire service components delivered on either ROUTEsessions or MMTP sessions. The described figure illustrates thefollowing signaling sequences. Receiver starts acquiring the SLTdescribed above. Each service identified by service_id delivered overROUTE sessions provides SLS bootstrapping information: PLPID(#1), sourceIP address (sIP1), destination IP address (dIP1), and destination portnumber (dPort1). Each service identified by service_id delivered overMMTP sessions provides SLS bootstrapping information: PLPID(#2),destination IP address (dIP2), and destination port number (dPort2).

For streaming services delivery using ROUTE, the receiver can acquireSLS fragments carried over the IP/UDP/LCT session and PLP; whereas forstreaming services delivery using MMTP, the receiver can acquire SLSfragments carried over an MMTP session and PLP. For service deliveryusing ROUTE, these SLS fragments include USBD/USD fragments, S-TSIDfragments, and MPD fragments. They are relevant to one service. USBD/USDfragments describe service layer properties and provide URI referencesto S-TSID fragments and URI references to MPD fragments. In other words,the USBD/USD may refer to S-TSID and MPD. For service delivery usingMMTP, the USBD references the MMT signaling's MPT message, the MP Tableof which provides identification of package ID and location informationfor assets belonging to the service. Here, an asset is a multimedia dataentity, and may refer to a data entity which is combined into one uniqueID and is used to generate one multimedia presentation. The asset maycorrespond to a service component included in one service. The MPTmessage is a message having the MP table of MMT. Here, the MP table maybe an MMT package table having information about content and an MMTasset. Details may be similar to a definition in MMT. Here, mediapresentation may correspond to a collection of data that establishesbounded/unbounded presentation of media content.

The S-TSID fragment provides component acquisition informationassociated with one service and mapping between DASH Representationsfound in the MPD and in the TSI corresponding to the component of theservice. The S-TSID can provide component acquisition information in theform of a TSI and the associated DASH representation identifier, andPLPID carrying DASH segments associated with the DASH representation. Bythe PLPID and TSI values, the receiver collects the audio/videocomponents from the service and begins buffering DASH media segmentsthen applies the appropriate decoding processes.

For USBD listing service components delivered on MMTP sessions, asillustrated by “Service #2” in the described figure, the receiver alsoacquires an MPT message with matching MMT_package_id to complete theSLS. An MPT message provides the full list of service componentscomprising a service and the acquisition information for each component.Component acquisition information includes MMTP session information, thePLPID carrying the session and the packet_id within that session.

According to a given embodiment, for example, in ROUTE, two or moreS-TSID fragments may be used. Each fragment may provide accessinformation related to LCT sessions delivering content of each service.

In ROUTE, S-TSID, USBD/USD, MPD, or an LCT session delivering S-TSID,USBD/USD or MPD may be referred to as a service signaling channel. InMMTP, USBD/UD, an MMT signaling message, or a packet flow delivering theMMTP or USBD/UD may be referred to as a service signaling channel.

Unlike the illustrated example, one ROUTE or MMTP session may bedelivered through a plurality of PLPs. In other words, one service maybe delivered through one or more PLPs. As described in the foregoing,one LCT session may be delivered through one PLP. Unlike the figure,according to a given embodiment, components included in one service maybe delivered through different ROUTE sessions. In addition, according toa given embodiment, components included in one service may be deliveredthrough different MMTP sessions. According to a given embodiment,components included in one service may be delivered separately through aROUTE session and an MMTP session. Although not illustrated, componentsincluded in one service may be delivered via broadband (hybriddelivery).

FIG. 5 illustrates a USBD fragment for ROUTE/DASH according to anembodiment of the present invention.

Hereinafter, a description will be given of SLS in delivery based onROUTE.

SLS provides detailed technical information to the receiver to enablethe discovery and access of services and their content components. Itcan include a set of XML-encoded metadata fragments carried over adedicated LCT session. That LCT session can be acquired using thebootstrap information contained in the SLT as described above. The SLSis defined on a per-service level, and it describes the characteristicsand access information of the service, such as a list of its contentcomponents and how to acquire them, and the receiver capabilitiesrequired to make a meaningful presentation of the service. In theROUTE/DASH system, for linear services delivery, the SLS consists of thefollowing metadata fragments: USBD, S-TSID and the DASH MPD. The SLSfragments can be delivered on a dedicated LCT transport session withTSI=0. According to a given embodiment, a TSI of a particular LCTsession (dedicated LCT session) in which an SLS fragment is deliveredmay have a different value. According to a given embodiment, an LCTsession in which an SLS fragment is delivered may be signaled using theSLT or another scheme.

ROUTE/DASH SLS can include the user service bundle description (USBD)and service-based transport session instance description (S-TSID)metadata fragments. These service signaling fragments are applicable toboth linear and application-based services. The USBD fragment containsservice identification, device capabilities information, references toother SLS fragments required to access the service and constituent mediacomponents, and metadata to enable the receiver to determine thetransport mode (broadcast and/or broadband) of service components. TheS-TSID fragment, referenced by the USBD, provides transport sessiondescriptions for the one or more ROUTE/LCT sessions in which the mediacontent components of a service are delivered, and descriptions of thedelivery objects carried in those LCT sessions. The USBD and S-TSID willbe described below.

In streaming content signaling in ROUTE-based delivery, a streamingcontent signaling component of SLS corresponds to an MPD fragment. TheMPD is typically associated with linear services for the delivery ofDASH Segments as streaming content. The MPD provides the resourceidentifiers for individual media components of the linear/streamingservice in the form of Segment URLs, and the context of the identifiedresources within the Media Presentation. Details of the MPD will bedescribed below.

In app-based enhancement signaling in ROUTE-based delivery, app-basedenhancement signaling pertains to the delivery of app-based enhancementcomponents, such as an application logic file, locally-cached mediafiles, network content items, or a notification stream. An applicationcan also retrieve locally-cached data over a broadband connection whenavailable.

Hereinafter, a description will be given of details of USBD/USDillustrated in the figure.

The top level or entry point SLS fragment is the USBD fragment. Anillustrated USBD fragment is an example of the present invention, basicfields of the USBD fragment not illustrated in the figure may beadditionally provided according to a given embodiment. As described inthe foregoing, the illustrated USBD fragment has an extended form, andmay have fields added to a basic configuration.

The illustrated USBD may have a bundleDescription root element. ThebundleDescription root element may have a userServiceDescriptionelement. The userServiceDescription element may correspond to aninstance for one service.

The userServiceDescription element may include @serviceId,@atsc:serviceId, @atsc:serviceStatus, @atsc:fullMPDUri, @atsc:sTSIDUri,name, serviceLanguage, atsc:capabilityCode and/or deliveryMethod.

@serviceId can be a globally unique URI that identifies a service,unique within the scope of the BSID. This parameter can be used to linkto ESG data (Service@globalServiceID).

@atsc:serviceId is a reference to corresponding service entry inLLS(SLT). The value of this attribute is the same value of serviceIdassigned to the entry.

@atsc:serviceStatus can specify the status of this service. The valueindicates whether this service is active or inactive. When set to “1”(true), that indicates service is active. When this field is not used,@atsc:serviceStatus may be set to a default value of 1.

@atsc:fullMPDUri can reference an MPD fragment which containsdescriptions for contents components of the service delivered overbroadcast and optionally, also over broadband.

@atsc:sTSIDUri can reference the S-TSID fragment which provides accessrelated parameters to the Transport sessions carrying contents of thisservice.

name can indicate name of the service as given by the lang attribute.name element can include lang attribute, which indicating language ofthe service name. The language can be specified according to XML datatypes.

serviceLanguage can represent available languages of the service. Thelanguage can be specified according to XML data types.

atsc:capabilityCode can specify the capabilities required in thereceiver to be able to create a meaningful presentation of the contentof this service. According to a given embodiment, this field may specifya predefined capability group. Here, the capability group may be a groupof capability attribute values for significant presentation. This fieldmay be omitted according to a given embodiment.

deliveryMethod can be a container of transport related informationpertaining to the contents of the service over broadcast and(optionally) broadband modes of access. Referring to data included inthe service, when the number of the data is N, delivery schemes forrespective data may be described by this element. The deliveryMethod mayinclude an r12:broadcastAppService element and an r12:unicastAppServiceelement. Each lower element may include a basePattern element as a lowerelement.

r12:broadcastAppService can be a DASH Representation delivered overbroadcast, in multiplexed or non-multiplexed form, containing thecorresponding media component(s) belonging to the service, across allPeriods of the affiliated media presentation. In other words, each ofthe fields may indicate DASH representation delivered through thebroadcast network.

r12:unicastAppService can be a DASH Representation delivered overbroadband, in multiplexed or non-multiplexed form, containing theconstituent media content component(s) belonging to the service, acrossall periods of the affiliated media presentation. In other words, eachof the fields may indicate DASH representation delivered via broadband.

basePattern can be a character pattern for use by the receiver to matchagainst any portion of the segment URL used by the DASH client torequest media segments of a parent representation under its containingperiod. A match implies that the corresponding requested media segmentis carried over broadcast transport. In a URL address for receiving DASHrepresentation expressed by each of the r12:broadcastAppService elementand the r12:unicastAppService element, a part of the URL, etc. may havea particular pattern. The pattern may be described by this field. Somedata may be distinguished using this information. The proposed defaultvalues may vary depending on embodiments. The “use” column illustratedin the figure relates to each field. Here, M may denote an essentialfield, 0 may denote an optional field, OD may denote an optional fieldhaving a default value, and CM may denote a conditional essential field.0 . . . 1 to 0 . . . N may indicate the number of available fields.

FIG. 6 illustrates an S-TSID fragment for ROUTE/DASH according to anembodiment of the present invention.

Hereinafter, a description will be given of the S-TSID illustrated inthe figure in detail.

S-TSID can be an SLS XML fragment which provides the overall sessiondescription information for transport session(s) which carry the contentcomponents of a service. The S-TSID is the SLS metadata fragment thatcontains the overall transport session description information for thezero or more ROUTE sessions and constituent LCT sessions in which themedia content components of a service are delivered. The S-TSID alsoincludes file metadata for the delivery object or object flow carried inthe LCT sessions of the service, as well as additional information onthe payload formats and content components carried in those LCTsessions.

Each instance of the S-TSID fragment is referenced in the USBD fragmentby the @atsc:sTSIDUri attribute of the userServiceDescription element.The illustrated S-TSID according to the present embodiment is expressedas an XML document. According to a given embodiment, the S-TSID may beexpressed in a binary format or as an XML document.

The illustrated S-TSID may have an S-TSID root element. The S-TSID rootelement may include @serviceId and/or RS.

@serviceID can be a reference corresponding service element in the USD.The value of this attribute can reference a service with a correspondingvalue of service_id.

The RS element may have information about a ROUTE session for deliveringthe service data. Service data or service components may be deliveredthrough a plurality of ROUTE sessions, and thus the number of RSelements may be 1 to N.

The RS element may include @bsid, @slpAddr, @dlpAddr, @dport, @PLPIDand/or LS.

@bsid can be an identifier of the broadcast stream within which thecontent component(s) of the broadcastAppService are carried. When thisattribute is absent, the default broadcast stream is the one whose PLPscarry SLS fragments for this service. Its value can be identical to thatof the broadcast_stream_id in the SLT.

@slpAddr can indicate source IP address. Here, the source IP address maybe a source IP address of a ROUTE session for delivering a servicecomponent included in the service. As described in the foregoing,service components of one service may be delivered through a pluralityof ROUTE sessions. Thus, the service components may be transmitted usinganother ROUTE session other than the ROUTE session for delivering theS-TSID. Therefore, this field may be used to indicate the source IPaddress of the ROUTE session. A default value of this field may be asource IP address of a current ROUTE session. When a service componentis delivered through another ROUTE session, and thus the ROUTE sessionneeds to be indicated, a value of this field may be a value of a sourceIP address of the ROUTE session. In this case, this field may correspondto M, that is, an essential field.

@dlpAddr can indicate destination IP address. Here, a destination IPaddress may be a destination IP address of a ROUTE session that deliversa service component included in a service. For a similar case to theabove description of @slpAddr, this field may indicate a destination IPaddress of a ROUTE session that delivers a service component. A defaultvalue of this field may be a destination IP address of a current ROUTEsession. When a service component is delivered through another ROUTEsession, and thus the ROUTE session needs to be indicated, a value ofthis field may be a value of a destination IP address of the ROUTEsession. In this case, this field may correspond to M, that is, anessential field.

@dport can indicate destination port. Here, a destination port may be adestination port of a ROUTE session that delivers a service componentincluded in a service. For a similar case to the above description of@slpAddr, this field may indicate a destination port of a ROUTE sessionthat delivers a service component. A default value of this field may bea destination port number of a current ROUTE session. When a servicecomponent is delivered through another ROUTE session, and thus the ROUTEsession needs to be indicated, a value of this field may be adestination port number value of the ROUTE session. In this case, thisfield may correspond to M, that is, an essential field.

@PLPID may be an ID of a PLP for a ROUTE session expressed by an RS. Adefault value may be an ID of a PLP of an LCT session including acurrent S-TSID. According to a given embodiment, this field may have anID value of a PLP for an LCT session for delivering an S-TSID in theROUTE session, and may have ID values of all PLPs for the ROUTE session.

An LS element may have information about an LCT session for delivering aservice data. Service data or service components may be deliveredthrough a plurality of LCT sessions, and thus the number of LS elementsmay be 1 to N.

The LS element may include @tsi, @PLPID, @bw, @startTime, @endTime,SrcFlow and/or RprFlow.

@tsi may indicate a TSI value of an LCT session for delivering a servicecomponent of a service.

@PLPID may have ID information of a PLP for the LCT session. This valuemay be overwritten on a basic ROUTE session value.

@bw may indicate a maximum bandwidth value. @startTime may indicate astart time of the LCT session. @endTime may indicate an end time of theLCT session. A SrcFlow element may describe a source flow of ROUTE. ARprFlow element may describe a repair flow of ROUTE.

The proposed default values may be varied according to an embodiment.The “use” column illustrated in the figure relates to each field. Here,M may denote an essential field, 0 may denote an optional field, OD maydenote an optional field having a default value, and CM may denote aconditional essential field. 0 . . . 1 to 0 . . . N may indicate thenumber of available fields.

Hereinafter, a description will be given of MPD for ROUTE/DASH.

The MPD is an SLS metadata fragment which contains a formalizeddescription of a DASH Media Presentation, corresponding to a linearservice of a given duration defined by the broadcaster (for example asingle TV program, or the set of contiguous linear TV programs over aperiod of time). The contents of the MPD provide the resourceidentifiers for Segments and the context for the identified resourceswithin the Media Presentation. The data structure and semantics of theMPD fragment can be according to the MPD defined by MPEG DASH.

One or more of the DASH Representations conveyed in the MPD can becarried over broadcast. The MPD may describe additional Representationsdelivered over broadband, e.g. in the case of a hybrid service, or tosupport service continuity in handoff from broadcast to broadcast due tobroadcast signal degradation (e.g. driving through a tunnel).

FIG. 7 illustrates a USBD/USD fragment for MMT according to anembodiment of the present invention.

MMT SLS for linear services comprises the USBD fragment and the MMTPackage (MP) table. The MP table is as described above. The USBDfragment contains service identification, device capabilitiesinformation, references to other SLS information required to access theservice and constituent media components, and the metadata to enable thereceiver to determine the transport mode (broadcast and/or broadband) ofthe service components. The MP table for MPU components, referenced bythe USBD, provides transport session descriptions for the MMTP sessionsin which the media content components of a service are delivered and thedescriptions of the Assets carried in those MMTP sessions.

The streaming content signaling component of the SLS for MPU componentscorresponds to the MP table defined in MMT. The MP table provides a listof MMT assets where each asset corresponds to a single service componentand the description of the location information for this component.

USBD fragments may also contain references to the S-TSID and the MPD asdescribed above, for service components delivered by the ROUTE protocoland the broadband, respectively. According to a given embodiment, indelivery through MMT, a service component delivered through the ROUTEprotocol is NRT data, etc. Thus, in this case, MPD may be unnecessary.In addition, in delivery through MMT, information about an LCT sessionfor delivering a service component, which is delivered via broadband, isunnecessary, and thus an S-TSID may be unnecessary. Here, an MMT packagemay be a logical collection of media data delivered using MMT. Here, anMMTP packet may refer to a formatted unit of media data delivered usingMMT. An MPU may refer to a generic container of independently decodabletimed/non-timed data. Here, data in the MPU is media codec agnostic.

Hereinafter, a description will be given of details of the USBD/USDillustrated in the figure.

The illustrated USBD fragment is an example of the present invention,and basic fields of the USBD fragment may be additionally providedaccording to an embodiment. As described in the foregoing, theillustrated USBD fragment has an extended form, and may have fieldsadded to a basic structure.

The illustrated USBD according to an embodiment of the present inventionis expressed as an XML document. According to a given embodiment, theUSBD may be expressed in a binary format or as an XML document.

The illustrated USBD may have a bundleDescription root element. ThebundleDescription root element may have a userServiceDescriptionelement. The userServiceDescription element may be an instance for oneservice.

The userServiceDescription element may include @serviceId,@atsc:serviceId, name, serviceLanguage, atsc:capabilityCode,atsc:Channel, atsc:mpuComponent, atsc:routeComponent,atsc:broadbandComponent and/or atsc:ComponentInfo.

Here, @serviceId, @atsc:serviceId, name, serviceLanguage, andatsc:capabilityCode may be as described above. The lang field below thename field may be as described above. atsc:capabilityCode may be omittedaccording to a given embodiment.

The userServiceDescription element may further include anatsc:contentAdvisoryRating element according to an embodiment. Thiselement may be an optional element. atsc:contentAdvisoryRating canspecify the content advisory rating. This field is not illustrated inthe figure.

atsc:Channel may have information about a channel of a service. Theatsc:Channel element may include @atsc:majorChannelNo,@atsc:minorChannelNo, @atsc:serviceLang, @atsc:serviceGenre,@atsc:serviceIcon and/or atsc:ServiceDescription. @atsc:majorChannelNo,@atsc:minorChannelNo, and @atsc:serviceLang may be omitted according toa given embodiment.

@atsc:majorChannelNo is an attribute that indicates the major channelnumber of the service.

@atsc:minorChannelNo is an attribute that indicates the minor channelnumber of the service.

@atsc:serviceLang is an attribute that indicates the primary languageused in the service.

@atsc:serviceGenre is an attribute that indicates primary genre of theservice.

@atsc:serviceIcon is an attribute that indicates the Uniform ResourceLocator (URL) for the icon used to represent this service.

atsc:ServiceDescription includes service description, possibly inmultiple languages. atsc:ServiceDescription includes can include@atsc:serviceDescrText and/or @atsc:serviceDescrLang.

@atsc:serviceDescrText is an attribute that indicates description of theservice.

@atsc:serviceDescrLang is an attribute that indicates the language ofthe serviceDescrText attribute above.

atsc:mpuComponent may have information about a content component of aservice delivered in a form of an MPU. atsc:mpuComponent may include@atsc:mmtPackageId and/or @atsc:nextMmtPackageId.

@atsc:mmtPackageId can reference a MMT Package for content components ofthe service delivered as MPUs.

@atsc:nextMmtPackageId can reference a MMT Package to be used after theone referenced by @atsc:mmtPackageId in time for content components ofthe service delivered as MPUs.

atsc:routeComponent may have information about a content component of aservice delivered through ROUTE. atsc:routeComponent may include@atsc:sTSIDUri, @sTSIDPlpld, @sTSIDDestinationIpAddress,@sTSIDDestinationUdpPort, @sTSIDSourceIpAddress,@sTSIDMajorProtocolVersion and/or @sTSIDMinorProtocolVersion.

@atsc:sTSIDUri can be a reference to the S-TSID fragment which providesaccess related parameters to the Transport sessions carrying contents ofthis service. This field may be the same as a URI for referring to anS-TSID in USBD for ROUTE described above. As described in the foregoing,in service delivery by the MMTP, service components, which are deliveredthrough NRT, etc., may be delivered by ROUTE. This field may be used torefer to the S-TSID therefor.

@sTSIDPlpld can be a string representing an integer number indicatingthe PLP ID of the physical layer pipe carrying the S-TSID for thisservice. (default: current physical layer pipe).

@sTSIDDestinationIpAddress can be a string containing the dotted-IPv4destination address of the packets carrying S-TSID for this service.(default: current MMTP session's source IP address)

@sTSIDDestinationUdpPort can be a string containing the port number ofthe packets carrying S-TSID for this service.

@sTSIDSourceIpAddress can be a string containing the dotted-IPv4 sourceaddress of the packets carrying S-TSID for this service.

@sTSIDMajorProtocolVersion can indicate major version number of theprotocol used to deliver the S-TSID for this service. Default value is1.

@sTSIDMinorProtocolVersion can indicate minor version number of theprotocol used to deliver the S-TSID for this service. Default value is0.

atsc:broadbandComponent may have information about a content componentof a service delivered via broadband. In other words,atsc:broadbandComponent may be a field on the assumption of hybriddelivery. atsc:broadbandComponent may further include @atsc:fullfMPDUri.

@atsc:fullfMPDUri can be a reference to an MPD fragment which containsdescriptions for contents components of the service delivered overbroadband.

An atsc:ComponentInfo field may have information about an availablecomponent of a service. The atsc:ComponentInfo field may haveinformation about a type, a role, a name, etc. of each component. Thenumber of atsc:ComponentInfo fields may correspond to the number (N) ofrespective components. The atsc:ComponentInfo field may include@atsc:componentType, @atsc:componentRole, @atsc:componentProtectedFlag,@atsc:componentld and/or @atsc:componentName.

@atsc:componentType is an attribute that indicates the type of thiscomponent. Value of 0 indicates an audio component. Value of 1 indicatesa video component. Value of 2 indicated a closed caption component.Value of 3 indicates an application component. Values 4 to 7 arereserved. A meaning of a value of this field may be differently setdepending on embodiments.

@atsc:componentRole is an attribute that indicates the role or kind ofthis component.

For audio (when componentType attribute above is equal to 0): values ofcomponentRole attribute are as follows: 0=Complete main, 1=Music andEffects, 2=Dialog, 3=Commentary, 4=Visually Impaired, 5=HearingImpaired, 6=Voice-Over, 7-254=reserved, 255=unknown.

For video (when componentType attribute above is equal to 1) values ofcomponentRole attribute are as follows: 0=Primary video, 1=Alternativecamera view, 2=Other alternative video component, 3=Sign language inset,4=Follow subject video, 5=3D video left view, 6=3D video right view,7=3D video depth information, 8=Part of video array <x,y> of <n,m>,9=Follow-Subject metadata, 10-254=reserved, 255=unknown.

For Closed Caption component (when componentType attribute above isequal to 2) values of componentRole attribute are as follows: 0=Normal,1=Easy reader, 2-254=reserved, 255=unknown.

When componentType attribute above is between 3 to 7, inclusive, thecomponentRole can be equal to 255. A meaning of a value of this fieldmay be differently set depending on embodiments.

@atsc:componentProtectedFlag is an attribute that indicates if thiscomponent is protected (e.g. encrypted). When this flag is set to avalue of 1 this component is protected (e.g. encrypted). When this flagis set to a value of 0 this component is not protected (e.g. encrypted).When not present the value of componentProtectedFlag attribute isinferred to be equal to 0. A meaning of a value of this field may bedifferently set depending on embodiments.

@atsc:componentld is an attribute that indicates the identifier of thiscomponent. The value of this attribute can be the same as the asset_idin the MP table corresponding to this component.

@atsc:componentName is an attribute that indicates the human readablename of this component.

The proposed default values may vary depending on embodiments. The “use”column illustrated in the figure relates to each field. Here, M maydenote an essential field, O may denote an optional field, OD may denotean optional field having a default value, and CM may denote aconditional essential field. 0 . . . 1 to 0 . . . N may indicate thenumber of available fields.

Hereinafter, a description will be given of MPD for MMT.

The Media Presentation Description is an SLS metadata fragmentcorresponding to a linear service of a given duration defined by thebroadcaster (for example a single TV program, or the set of contiguouslinear TV programs over a period of time). The contents of the MPDprovide the resource identifiers for segments and the context for theidentified resources within the media presentation. The data structureand semantics of the MPD can be according to the MPD defined by MPEGDASH.

In the present embodiment, an MPD delivered by an MMTP session describesRepresentations delivered over broadband, e.g. in the case of a hybridservice, or to support service continuity in handoff from broadcast tobroadband due to broadcast signal degradation (e.g. driving under amountain or through a tunnel).

Hereinafter, a description will be given of an MMT signaling message forMMT.

When MMTP sessions are used to carry a streaming service, MMT signalingmessages defined by MMT are delivered by MMTP packets according tosignaling message mode defined by MMT. The value of the packet_id fieldof MMTP packets carrying service layer signaling is set to ‘00’ exceptfor MMTP packets carrying MMT signaling messages specific to an asset,which can be set to the same packet_id value as the MMTP packetscarrying the asset. Identifiers referencing the appropriate package foreach service are signaled by the USBD fragment as described above. MMTPackage Table (MPT) messages with matching MMT_package_id can bedelivered on the MMTP session signaled in the SLT. Each MMTP sessioncarries MMT signaling messages specific to its session or each assetdelivered by the MMTP session.

In other words, it is possible to access USBD of the MMTP session byspecifying an IP destination address/port number, etc. of a packethaving the SLS for a particular service in the SLT. As described in theforegoing, a packet ID of an MMTP packet carrying the SLS may bedesignated as a particular value such as 00, etc. It is possible toaccess an MPT message having a matched packet ID using theabove-described package IP information of USBD. As described below, theMPT message may be used to access each service component/asset.

The following MMTP messages can be delivered by the MMTP sessionsignaled in the SLT.

MMT Package Table (MPT) message: This message carries an MP (MMTPackage) table which contains the list of all Assets and their locationinformation as defined by MMT. If an Asset is delivered by a PLPdifferent from the current PLP delivering the MP table, the identifierof the PLP carrying the asset can be provided in the MP table usingphysical layer pipe identifier descriptor. The physical layer pipeidentifier descriptor will be described below.

MMT ATSC3 (MA3) message mmt_atsc3_message( ): This message carriessystem metadata specific for services including service layer signalingas described above. mmt_atsc3_message( ) will be described below.

The following MMTP messages can be delivered by the MMTP sessionsignaled in the SLT, if required.

Media Presentation Information (MPI) message: This message carries anMPI table which contains the whole document or a subset of a document ofpresentation information. An MP table associated with the MPI table alsocan be delivered by this message.

Clock Relation Information (CRI) message: This message carries a CRItable which contains clock related information for the mapping betweenthe NTP timestamp and the MPEG-2 STC. According to a given embodiment,the CRI message may not be delivered through the MMTP session.

The following MMTP messages can be delivered by each MMTP sessioncarrying streaming content.

Hypothetical Receiver Buffer Model message: This message carriesinformation required by the receiver to manage its buffer.

Hypothetical Receiver Buffer Model Removal message: This message carriesinformation required by the receiver to manage its MMT de-capsulationbuffer.

Hereinafter, a description will be given of mmt_atsc3_message( )corresponding to one of MMT signaling messages. An MMT Signaling messagemmt_atsc3_message( ) is defined to deliver information specific toservices according to the present invention described above. Thesignaling message may include message ID, version, and/or length fieldscorresponding to basic fields of the MMT signaling message. A payload ofthe signaling message may include service ID information, content typeinformation, content version information, content compressioninformation and/or URI information. The content type information mayindicate a type of data included in the payload of the signalingmessage. The content version information may indicate a version of dataincluded in the payload, and the content compression information mayindicate a type of compression applied to the data. The URI informationmay have URI information related to content delivered by the message.

Hereinafter, a description will be given of the physical layer pipeidentifier descriptor.

The physical layer pipe identifier descriptor is a descriptor that canbe used as one of descriptors of the MP table described above. Thephysical layer pipe identifier descriptor provides information about thePLP carrying an asset. If an asset is delivered by a PLP different fromthe current PLP delivering the MP table, the physical layer pipeidentifier descriptor can be used as an asset descriptor in theassociated MP table to identify the PLP carrying the asset. The physicallayer pipe identifier descriptor may further include BSID information inaddition to PLP ID information. The BSID may be an ID of a broadcaststream that delivers an MMTP packet for an asset described by thedescriptor.

FIG. 8 illustrates a link layer protocol architecture according to anembodiment of the present invention.

Hereinafter, a link layer will be described.

The link layer is the layer between the physical layer and the networklayer, and transports the data from the network layer to the physicallayer at the sending side and transports the data from the physicallayer to the network layer at the receiving side. The purpose of thelink layer includes abstracting all input packet types into a singleformat for processing by the physical layer, ensuring flexibility andfuture extensibility for as yet undefined input types. In addition,processing within the link layer ensures that the input data can betransmitted in an efficient manner, for example by providing options tocompress redundant information in the headers of input packets. Theoperations of encapsulation, compression and so on are referred to asthe link layer protocol and packets created using this protocol arecalled link layer packets. The link layer may perform functions such aspacket encapsulation, overhead reduction and/or signaling transmission,etc.

Hereinafter, packet encapsulation will be described. Link layer protocolallows encapsulation of any type of packet, including ones such as IPpackets and MPEG-2 TS. Using link layer protocol, the physical layerneed only process one single packet format, independent of the networklayer protocol type (here we consider MPEG-2 TS packet as a kind ofnetwork layer packet.) Each network layer packet or input packet istransformed into the payload of a generic link layer packet.Additionally, concatenation and segmentation can be performed in orderto use the physical layer resources efficiently when the input packetsizes are particularly small or large.

As described in the foregoing, segmentation may be used in packetencapsulation. When the network layer packet is too large to processeasily in the physical layer, the network layer packet is divided intotwo or more segments. The link layer packet header includes protocolfields to perform segmentation on the sending side and reassembly on thereceiving side. When the network layer packet is segmented, each segmentcan be encapsulated to link layer packet in the same order as originalposition in the network layer packet. Also each link layer packet whichincludes a segment of network layer packet can be transported to PHYlayer consequently.

As described in the foregoing, concatenation may be used in packetencapsulation. When the network layer packet is small enough for thepayload of a link layer packet to include several network layer packets,the link layer packet header includes protocol fields to performconcatenation. The concatenation is combining of multiple small sizednetwork layer packets into one payload. When the network layer packetsare concatenated, each network layer packet can be concatenated topayload of link layer packet in the same order as original input order.Also each packet which constructs a payload of link layer packet can bewhole packet, not a segment of packet.

Hereinafter, overhead reduction will be described. Use of the link layerprotocol can result in significant reduction in overhead for transportof data on the physical layer. The link layer protocol according to thepresent invention may provide IP overhead reduction and/or MPEG-2 TSoverhead reduction. In IP overhead reduction, IP packets have a fixedheader format, however some of the information which is needed in acommunication environment may be redundant in a broadcast environment.Link layer protocol provides mechanisms to reduce the broadcast overheadby compressing headers of IP packets. In MPEG-2 TS overhead reduction,link layer protocol provides sync byte removal, null packet deletionand/or common header removal (compression). First, sync byte removalprovides an overhead reduction of one byte per TS packet, secondly anull packet deletion mechanism removes the 188 byte null TS packets in amanner that they can be re-inserted at the receiver and finally a commonheader removal mechanism.

For signaling transmission, in the link layer protocol, a particularformat for the signaling packet may be provided for link layersignaling, which will be described below.

In the illustrated link layer protocol architecture according to anembodiment of the present invention, link layer protocol takes as inputnetwork layer packets such as IPv4, MPEG-2 TS and so on as inputpackets. Future extension indicates other packet types and protocolwhich is also possible to be input in link layer. Link layer protocolalso specifies the format and signaling for any link layer signaling,including information about mapping to specific channel to the physicallayer. Figure also shows how ALP incorporates mechanisms to improve theefficiency of transmission, via various header compression and deletionalgorithms. In addition, the link layer protocol may basicallyencapsulate input packets.

FIG. 9 illustrates a structure of a base header of a link layer packetaccording to an embodiment of the present invention. Hereinafter, thestructure of the header will be described.

A link layer packet can include a header followed by the data payload.The header of a link layer packet can include a base header, and mayinclude an additional header depending on the control fields of the baseheader. The presence of an optional header is indicated from flag fieldsof the additional header. According to a given embodiment, a fieldindicating the presence of an additional header and an optional headermay be positioned in the base header.

Hereinafter, the structure of the base header will be described. Thebase header for link layer packet encapsulation has a hierarchicalstructure. The base header can be two bytes in length and is the minimumlength of the link layer packet header.

The illustrated base header according to the present embodiment mayinclude a Packet_Type field, a PC field and/or a length field. Accordingto a given embodiment, the base header may further include an HM fieldor an S/C field.

Packet_Type field can be a 3-bit field that indicates the originalprotocol or packet type of the input data before encapsulation into alink layer packet. An IPv4 packet, a compressed IP packet, a link layersignaling packet, and other types of packets may have the base headerstructure and may be encapsulated. However, according to a givenembodiment, the MPEG-2 TS packet may have a different particularstructure, and may be encapsulated. When the value of Packet_Type is“000”, “001” “100” or “111”, that is the original data type of an ALPpacket is one of an IPv4 packet, a compressed IP packet, link layersignaling or extension packet. When the MPEG-2 TS packet isencapsulated, the value of Packet_Type can be “010.” Other values of thePacket_Type field may be reserved for future use.

Payload_Configuration (PC) field can be a 1-bit field that indicates theconfiguration of the payload. A value of 0 can indicate that the linklayer packet carries a single, whole input packet and the followingfield is the Header_Mode field. A value of 1 can indicate that the linklayer packet carries more than one input packet (concatenation) or apart of a large input packet (segmentation) and the following field isthe Segmentation_Concatenation field.

Header_Mode (HM) field can be a 1-bit field, when set to 0, that canindicate there is no additional header, and that the length of thepayload of the link layer packet is less than 2048 bytes. This value maybe varied depending on embodiments. A value of 1 can indicate that anadditional header for single packet defined below is present followingthe Length field. In this case, the length of the payload is larger than2047 bytes and/or optional features can be used (sub streamidentification, header extension, etc.). This value may be varieddepending on embodiments. This field can be present only whenPayload_Configuration field of the link layer packet has a value of 0.

Segmentation_Concatenation (S/C) field can be a 1-bit field, when set to0, that can indicate that the payload carries a segment of an inputpacket and an additional header for segmentation defined below ispresent following the Length field. A value of 1 can indicate that thepayload carries more than one complete input packet and an additionalheader for concatenation defined below is present following the Lengthfield. This field can be present only when the value ofPayload_Configuration field of the ALP packet is 1.

Length field can be a 11-bit field that indicates the 11 leastsignificant bits (LSBs) of the length in bytes of payload carried by thelink layer packet. When there is a Length_MSB field in the followingadditional header, the length field is concatenated with the Length_MSBfield, and is the LSB to provide the actual total length of the payload.The number of bits of the length field may be changed to another valuerather than 11 bits.

Following types of packet configuration are thus possible: a singlepacket without any additional header, a single packet with an additionalheader, a segmented packet and a concatenated packet. According to agiven embodiment, more packet configurations may be made through acombination of each additional header, an optional header, an additionalheader for signaling information to be described below, and anadditional header for time extension.

FIG. 10 illustrates a structure of an additional header of a link layerpacket according to an embodiment of the present invention.

Various types of additional headers may be present. Hereinafter, adescription will be given of an additional header for a single packet.

This additional header for single packet can be present when Header_Mode(HM)=“1.” The Header_Mode (HM) can be set to 1 when the length of thepayload of the link layer packet is larger than 2047 bytes or when theoptional fields are used. The additional header for single packet isshown in Figure (tsib10010).

Length_MSB field can be a 5-bit field that can indicate the mostsignificant bits (MSBs) of the total payload length in bytes in thecurrent link layer packet, and is concatenated with the Length fieldcontaining the 11 least significant bits (LSBs) to obtain the totalpayload length. The maximum length of the payload that can be signaledis therefore 65535 bytes. The number of bits of the length field may bechanged to another value rather than 11 bits. In addition, the number ofbits of the Length_MSB field may be changed, and thus a maximumexpressible payload length may be changed. According to a givenembodiment, each length field may indicate a length of a whole linklayer packet rather than a payload.

SIF (Sub stream Identifier Flag) field can be a 1-bit field that canindicate whether the sub stream ID (SID) is present after the HEF fieldor not. When there is no SID in this link layer packet, SIF field can beset to 0. When there is a SID after HEF field in the link layer packet,SIF can be set to 1. The detail of SID is described below.

HEF (Header Extension Flag) field can be a 1-bit field that canindicate, when set to 1 additional header is present for futureextension. A value of 0 can indicate that this extension header is notpresent.

Hereinafter, a description will be given of an additional header whensegmentation is used.

This additional header (tsib10020) can be present whenSegmentation_Concatenation (S/C)=“0.” Segment_Sequence_Number can be a5-bit unsigned integer that can indicate the order of the correspondingsegment carried by the link layer packet. For the link layer packetwhich carries the first segment of an input packet, the value of thisfield can be set to 0x0. This field can be incremented by one with eachadditional segment belonging to the segmented input packet.

Last_Segment_Indicator (LSI) can be a 1-bit field that can indicate,when set to 1, that the segment in this payload is the last one of inputpacket. A value of 0, can indicate that it is not last segment.

SIF (Sub stream Identifier Flag) can be a 1-bit field that can indicatewhether the SID is present after the HEF field or not. When there is noSID in the link layer packet, SIF field can be set to 0. When there is aSID after the HEF field in the link layer packet, SIF can be set to 1.

HEF (Header Extension Flag) can be a This 1-bit field that can indicate,when set to 1, that the optional header extension is present after theadditional header for future extensions of the link layer header. Avalue of 0 can indicate that optional header extension is not present.

According to a given embodiment, a packet ID field may be additionallyprovided to indicate that each segment is generated from the same inputpacket. This field may be unnecessary and thus be omitted when segmentsare transmitted in order.

Hereinafter, a description will be given of an additional header whenconcatenation is used.

This additional header (tsib10030) can be present whenSegmentation_Concatenation (S/C)=“1.”

Length_MSB can be a 4-bit field that can indicate MSB bits of thepayload length in bytes in this link layer packet. The maximum length ofthe payload is 32767 bytes for concatenation. As described in theforegoing, a specific numeric value may be changed.

Count can be a field that can indicate the number of the packetsincluded in the link layer packet. The number of the packets included inthe link layer packet, 2 can be set to this field. So, its maximum valueof concatenated packets in a link layer packet is 9. A scheme in whichthe count field indicates the number may be varied depending onembodiments. That is, the numbers from 1 to 8 may be indicated.

HEF (Header Extension Flag) can be a 1-bit field that can indicate, whenset to 1 the optional header extension is present after the additionalheader for future extensions of the link layer header. A value of 0, canindicate extension header is not present.

Component_Length can be a 12-bit length field that can indicate thelength in byte of each packet. Component_Length fields are included inthe same order as the packets present in the payload except lastcomponent packet. The number of length field can be indicated by(Count+1). According to a given embodiment, length fields, the number ofwhich is the same as a value of the count field, may be present. When alink layer header consists of an odd number of Component_Length, fourstuffing bits can follow after the last Component_Length field. Thesebits can be set to 0. According to a given embodiment, aComponent_length field indicating a length of a last concatenated inputpacket may not be present. In this case, the length of the lastconcatenated input packet may correspond to a length obtained bysubtracting a sum of values indicated by respective Component_lengthfields from a whole payload length.

Hereinafter, the optional header will be described.

As described in the foregoing, the optional header may be added to arear of the additional header. The optional header field can contain SIDand/or header extension. The SID is used to filter out specific packetstream in the link layer level. One example of SID is the role ofservice identifier in a link layer stream carrying multiple services.The mapping information between a service and the SID valuecorresponding to the service can be provided in the SLT, if applicable.The header extension contains extended field for future use. Receiverscan ignore any header extensions which they do not understand.

SID (Sub stream Identifier) can be a 8-bit field that can indicate thesub stream identifier for the link layer packet. If there is optionalheader extension, SID present between additional header and optionalheader extension.

Header_Extension ( ) can include the fields defined below.

Extension_Type can be an 8-bit field that can indicate the type of theHeader_Extension ( ).

Extension_Length can be a 8-bit field that can indicate the length ofthe Header Extension ( ) in bytes counting from the next byte to thelast byte of the Header_Extension ( ).

Extension_Byte can be a byte representing the value of theHeader_Extension ( ).

FIG. 11 illustrates a structure of an additional header of a link layerpacket according to another embodiment of the present invention.

Hereinafter, a description will be given of an additional header forsignaling information.

How link layer signaling is incorporated into link layer packets are asfollows. Signaling packets are identified by when the Packet_Type fieldof the base header is equal to 100.

Figure (tsib11010) shows the structure of the link layer packetscontaining additional header for signaling information. In addition tothe link layer header, the link layer packet can consist of twoadditional parts, additional header for signaling information and theactual signaling data itself. The total length of the link layersignaling packet is shown in the link layer packet header.

The additional header for signaling information can include followingfields. According to a given embodiment, some fields may be omitted.

Signaling_Type can be an 8-bit field that can indicate the type ofsignaling.

Signaling_Type_Extension can be a 16-bit filed that can indicate theattribute of the signaling. Detail of this field can be defined insignaling specification.

Signaling_Version can be an 8-bit field that can indicate the version ofsignaling.

Signaling_Format can be a 2-bit field that can indicate the data formatof the signaling data. Here, a signaling format may refer to a dataformat such as a binary format, an XML format, etc.

Signaling_Encoding can be a 2-bit field that can specify theencoding/compression format. This field may indicate whether compressionis not performed and which type of compression is performed.

Hereinafter, a description will be given of an additional header forpacket type extension.

In order to provide a mechanism to allow an almost unlimited number ofadditional protocol and packet types to be carried by link layer in thefuture, the additional header is defined. Packet type extension can beused when Packet_type is 111 in the base header as described above.Figure (tsib11020) shows the structure of the link layer packetscontaining additional header for type extension.

The additional header for type extension can include following fields.According to a given embodiment, some fields may be omitted.

extended_type can be a 16-bit field that can indicate the protocol orpacket type of the input encapsulated in the link layer packet aspayload. This field cannot be used for any protocol or packet typealready defined by Packet_Type field.

FIG. 12 illustrates a header structure of a link layer packet for anMPEG-2 TS packet and an encapsulation process thereof according to anembodiment of the present invention.

Hereinafter, a description will be given of a format of the link layerpacket when the MPEG-2 TS packet is input as an input packet.

In this case, the Packet_Type field of the base header is equal to 010.Multiple TS packets can be encapsulated within each link layer packet.The number of TS packets is signaled via the NUMTS field. In this case,as described in the foregoing, a particular link layer packet headerformat may be used.

Link layer provides overhead reduction mechanisms for MPEG-2 TS toenhance the transmission efficiency. The sync byte (0x47) of each TSpacket can be deleted. The option to delete NULL packets and similar TSheaders is also provided.

In order to avoid unnecessary transmission overhead, TS null packets(PID=0x1FFF) may be removed. Deleted null packets can be recovered inreceiver side using DNP field. The DNP field indicates the count ofdeleted null packets. Null packet deletion mechanism using DNP field isdescribed below.

In order to achieve more transmission efficiency, similar header ofMPEG-2 TS packets can be removed. When two or more successive TS packetshave sequentially increased continuity counter fields and other headerfields are the same, the header is sent once at the first packet and theother headers are deleted. HDM field can indicate whether the headerdeletion is performed or not. Detailed procedure of common TS headerdeletion is described below.

When all three overhead reduction mechanisms are performed, overheadreduction can be performed in sequence of sync removal, null packetdeletion, and common header deletion. According to a given embodiment, aperformance order of respective mechanisms may be changed. In addition,some mechanisms may be omitted according to a given embodiment.

The overall structure of the link layer packet header when using MPEG-2TS packet encapsulation is depicted in Figure (tsib12010).

Hereinafter, a description will be given of each illustrated field.Packet_Type can be a 3-bit field that can indicate the protocol type ofinput packet as describe above. For MPEG-2 TS packet encapsulation, thisfield can always be set to 010.

NUMTS (Number of TS packets) can be a 4-bit field that can indicate thenumber of TS packets in the payload of this link layer packet. A maximumof 16 TS packets can be supported in one link layer packet. The value ofNUMTS=0 can indicate that 16 TS packets are carried by the payload ofthe link layer packet. For all other values of NUMTS, the same number ofTS packets are recognized, e.g. NUMTS=0001 means one TS packet iscarried.

AHF (Additional Header Flag) can be a field that can indicate whetherthe additional header is present of not. A value of 0 indicates thatthere is no additional header. A value of 1 indicates that an additionalheader of length 1-byte is present following the base header. If null TSpackets are deleted or TS header compression is applied this field canbe set to 1. The additional header for TS packet encapsulation consistsof the following two fields and is present only when the value of AHF inthis link layer packet is set to 1.

HDM (Header Deletion Mode) can be a 1-bit field that indicates whetherTS header deletion can be applied to this link layer packet. A value of1 indicates that TS header deletion can be applied. A value of “0”indicates that the TS header deletion method is not applied to this linklayer packet.

DNP (Deleted Null Packets) can be a 7-bit field that indicates thenumber of deleted null TS packets prior to this link layer packet. Amaximum of 128 null TS packets can be deleted. When HDM=0 the value ofDNP=0 can indicate that 128 null packets are deleted. When HDM=1 thevalue of DNP=0 can indicate that no null packets are deleted. For allother values of DNP, the same number of null packets are recognized,e.g. DNP=5 means 5 null packets are deleted.

The number of bits of each field described above may be changed.According to the changed number of bits, a minimum/maximum value of avalue indicated by the field may be changed. These numbers may bechanged by a designer.

Hereinafter, SYNC byte removal will be described.

When encapsulating TS packets into the payload of a link layer packet,the SYNC byte (0x47) from the start of each TS packet can be deleted.Hence the length of the MPEG2-TS packet encapsulated in the payload ofthe link layer packet is always of length 187 bytes (instead of 188bytes originally).

Hereinafter, null packet deletion will be described.

Transport Stream rules require that bit rates at the output of atransmitter's multiplexer and at the input of the receiver'sde-multiplexer are constant in time and the end-to-end delay is alsoconstant. For some Transport Stream input signals, null packets may bepresent in order to accommodate variable bitrate services in a constantbitrate stream. In this case, in order to avoid unnecessary transmissionoverhead, TS null packets (that is TS packets with PID=0x1FFF) may beremoved. The process is carried-out in a way that the removed nullpackets can be re-inserted in the receiver in the exact place where theywere originally, thus guaranteeing constant bitrate and avoiding theneed for PCR time stamp updating.

Before generation of a link layer packet, a counter called DNP (DeletedNull-Packets) can first be reset to zero and then incremented for eachdeleted null packet preceding the first non-null TS packet to beencapsulated into the payload of the current link layer packet. Then agroup of consecutive useful TS packets is encapsulated into the payloadof the current link layer packet and the value of each field in itsheader can be determined. After the generated link layer packet isinjected to the physical layer, the DNP is reset to zero. When DNPreaches its maximum allowed value, if the next packet is also a nullpacket, this null packet is kept as a useful packet and encapsulatedinto the payload of the next link layer packet. Each link layer packetcan contain at least one useful TS packet in its payload.

Hereinafter, TS packet header deletion will be described. TS packetheader deletion may be referred to as TS packet header compression.

When two or more successive TS packets have sequentially increasedcontinuity counter fields and other header fields are the same, theheader is sent once at the first packet and the other headers aredeleted. When the duplicated MPEG-2 TS packets are included in two ormore successive TS packets, header deletion cannot be applied intransmitter side. HDM field can indicate whether the header deletion isperformed or not. When TS header deletion is performed, HDM can be setto 1. In the receiver side, using the first packet header, the deletedpacket headers are recovered, and the continuity counter is restored byincreasing it in order from that of the first header.

An example tsib12020 illustrated in the figure is an example of aprocess in which an input stream of a TS packet is encapsulated into alink layer packet. First, a TS stream including TS packets having SYNCbyte (0x47) may be input. First, sync bytes may be deleted through async byte deletion process. In this example, it is presumed that nullpacket deletion is not performed.

Here, it is presumed that packet headers of eight TS packets have thesame field values except for CC, that is, a continuity counter fieldvalue. In this case, TS packet deletion/compression may be performed.Seven remaining TS packet headers are deleted except for a first TSpacket header corresponding to CC=1. The processed TS packets may beencapsulated into a payload of the link layer packet.

In a completed link layer packet, a Packet_Type field corresponds to acase in which TS packets are input, and thus may have a value of 010. ANUMTS field may indicate the number of encapsulated TS packets. An AHFfield may be set to 1 to indicate the presence of an additional headersince packet header deletion is performed. An HDM field may be set to 1since header deletion is performed. DNP may be set to 0 since nullpacket deletion is not performed.

FIG. 13 illustrates an example of adaptation modes in IP headercompression according to an embodiment of the present invention(transmitting side).

Hereinafter, IP header compression will be described.

In the link layer, IP header compression/decompression scheme can beprovided. IP header compression can include two parts: headercompressor/decompressor and adaptation module. The header compressionscheme can be based on the Robust Header Compression (RoHC). Inaddition, for broadcasting usage, adaptation function is added.

In the transmitter side, ROHC compressor reduces the size of header foreach packet. Then, adaptation module extracts context information andbuilds signaling information from each packet stream. In the receiverside, adaptation module parses the signaling information associated withthe received packet stream and attaches context information to thereceived packet stream. ROHC decompressor reconstructs the original IPpacket by recovering the packet header.

The header compression scheme can be based on the RoHC as describedabove. In particular, in the present system, an RoHC framework canoperate in a unidirectional mode (U mode) of the RoHC. In addition, inthe present system, it is possible to use an RoHC UDP header compressionprofile which is identified by a profile identifier of 0x0002.

Hereinafter, adaptation will be described.

In case of transmission through the unidirectional link, if a receiverhas no information of context, decompressor cannot recover the receivedpacket header until receiving full context. This may cause channelchange delay and turn on delay. For this reason, context information andconfiguration parameters between compressor and decompressor can bealways sent with packet flow.

The Adaptation function provides out-of-band transmission of theconfiguration parameters and context information. Out-of-bandtransmission can be done through the link layer signaling. Therefore,the adaptation function is used to reduce the channel change delay anddecompression error due to loss of context information.

Hereinafter, extraction of context information will be described.

Context information may be extracted using various schemes according toadaptation mode. In the present invention, three examples will bedescribed below. The scope of the present invention is not restricted tothe examples of the adaptation mode to be described below. Here, theadaptation mode may be referred to as a context extraction mode.

Adaptation Mode 1 (not illustrated) may be a mode in which no additionaloperation is applied to a basic RoHC packet stream. In other words, theadaptation module may operate as a buffer in this mode. Therefore, inthis mode, context information may not be included in link layersignaling

In Adaptation Mode 2 (tsib13010), the adaptation module can detect theIR packet from ROHC packet flow and extract the context information(static chain). After extracting the context information, each IR packetcan be converted to an IR-DYN packet. The converted IR-DYN packet can beincluded and transmitted inside the ROHC packet flow in the same orderas IR packet, replacing the original packet.

In Adaptation Mode 3 (tsib13020), the adaptation module can detect theIR and IR-DYN packet from ROHC packet flow and extract the contextinformation. The static chain and dynamic chain can be extracted from IRpacket and dynamic chain can be extracted from IR-DYN packet. Afterextracting the context information, each IR and IR-DYN packet can beconverted to a compressed packet. The compressed packet format can bethe same with the next packet of IR or IR-DYN packet. The convertedcompressed packet can be included and transmitted inside the ROHC packetflow in the same order as IR or IR-DYN packet, replacing the originalpacket.

Signaling (context) information can be encapsulated based ontransmission structure. For example, context information can beencapsulated to the link layer signaling. In this case, the packet typevalue can be set to “100.”

In the above-described Adaptation Modes 2 and 3, a link layer packet forcontext information may have a packet type field value of 100. Inaddition, a link layer packet for compressed IP packets may have apacket type field value of 001. The values indicate that each of thesignaling information and the compressed IP packets are included in thelink layer packet as described above.

Hereinafter, a description will be given of a method of transmitting theextracted context information.

The extracted context information can be transmitted separately fromROHC packet flow, with signaling data through specific physical datapath. The transmission of context depends on the configuration of thephysical layer path. The context information can be sent with other linklayer signaling through the signaling data pipe.

In other words, the link layer packet having the context information maybe transmitted through a signaling PLP together with link layer packetshaving other link layer signaling information (Packet_Type=100).Compressed IP packets from which context information is extracted may betransmitted through a general PLP (Packet_Type=001). Here, depending onembodiments, the signaling PLP may refer to an L1 signaling path. Inaddition, depending on embodiments, the signaling PLP may not beseparated from the general PLP, and may refer to a particular andgeneral PLP through which the signaling information is transmitted.

At a receiving side, prior to reception of a packet stream, a receivermay need to acquire signaling information. When receiver decodes initialPLP to acquire the signaling information, the context signaling can bealso received. After the signaling acquisition is done, the PLP toreceive packet stream can be selected. In other words, the receiver mayacquire the signaling information including the context information byselecting the initial PLP. Here, the initial PLP may be theabove-described signaling PLP. Thereafter, the receiver may select a PLPfor acquiring a packet stream. In this way, the context information maybe acquired prior to reception of the packet stream.

After the PLP for acquiring the packet stream is selected, theadaptation module can detect IR-DYN packet form received packet flow.Then, the adaptation module parses the static chain from the contextinformation in the signaling data. This is similar to receiving the IRpacket. For the same context identifier, IR-DYN packet can be recoveredto IR packet. Recovered ROHC packet flow can be sent to ROHCdecompressor. Thereafter, decompression may be started.

FIG. 14 illustrates a link mapping table (LMT) and an RoHC-U descriptiontable according to an embodiment of the present invention.

Hereinafter, link layer signaling will be described.

Generally, link layer signaling is operates under IP level. At thereceiver side, link layer signaling can be obtained earlier than IPlevel signaling such as Service List Table (SLT) and Service LayerSignaling (SLS). Therefore, link layer signaling can be obtained beforesession establishment.

For link layer signaling, there can be two kinds of signaling accordinginput path: internal link layer signaling and external link layersignaling. The internal link layer signaling is generated in link layerat transmitter side. And the link layer takes the signaling fromexternal module or protocol. This kind of signaling information isconsidered as external link layer signaling. If some signaling need tobe obtained prior to IP level signaling, external signaling istransmitted in format of link layer packet.

The link layer signaling can be encapsulated into link layer packet asdescribed above. The link layer packets can carry any format of linklayer signaling, including binary and XML. The same signalinginformation may not be transmitted in different formats for the linklayer signaling.

Internal link layer signaling may include signaling information for linkmapping. The Link Mapping Table (LMT) provides a list of upper layersessions carried in a PLP. The LMT also provides addition informationfor processing the link layer packets carrying the upper layer sessionsin the link layer.

An example of the LMT (tsib14010) according to the present invention isillustrated.

signaling_type can be an 8-bit unsigned integer field that indicates thetype of signaling carried by this table. The value of signaling_typefield for Link Mapping Table (LMT) can be set to 0x01.

PLP_ID can be an 8-bit field that indicates the PLP corresponding tothis table.

num_session can be an 8-bit unsigned integer field that provides thenumber of upper layer sessions carried in the PLP identified by theabove PLP_ID field. When the value of signaling_type field is 0x01, thisfield can indicate the number of UDP/IP sessions in the PLP.

src_IP_add can be a 32-bit unsigned integer field that contains thesource IP address of an upper layer session carried in the PLPidentified by the PLP_ID field.

dst_IP_add can be a 32-bit unsigned integer field that contains thedestination IP address of an upper layer session carried in the PLPidentified by the PLP_ID field.

src_UDP_port can be a 16-bit unsigned integer field that represents thesource UDP port number of an upper layer session carried in the PLPidentified by the PLP_ID field.

dst_UDP_port can be a 16-bit unsigned integer field that represents thedestination UDP port number of an upper layer session carried in the PLPidentified by the PLP_ID field.

SID_flag can be a 1-bit Boolean field that indicates whether the linklayer packet carrying the upper layer session identified by above 4fields, Src_IP_add, Dst_IP_add, Src_UDP_Port and Dst_UDP_Port, has anSID field in its optional header. When the value of this field is set to0, the link layer packet carrying the upper layer session may not havean SID field in its optional header. When the value of this field is setto 1, the link layer packet carrying the upper layer session can have anSID field in its optional header and the value the SID field can be sameas the following SID field in this table.

compressed_flag can be a 1-bit Boolean field that indicates whether theheader compression is applied the link layer packets carrying the upperlayer session identified by above 4 fields, Src_IP_add, Dst_IP_add,Src_UDP_Port and Dst_UDP_Port. When the value of this field is set to 0,the link layer packet carrying the upper layer session may have a valueof 0x00 of Packet_Type field in its base header. When the value of thisfield is set to 1, the link layer packet carrying the upper layersession may have a value of 0x01 of Packet_Type field in its base headerand the Context_ID field can be present.

SID can be an 8-bit unsigned integer field that indicates sub streamidentifier for the link layer packets carrying the upper layer sessionidentified by above 4 fields, Src_IP_add, Dst_IP_add, Src_UDP_Port andDst_UDP_Port. This field can be present when the value of SID_flag isequal to 1.

context_id can be an 8-bit field that provides a reference for thecontext id (CID) provided in the ROHC-U description table. This fieldcan be present when the value of compressed_flag is equal to 1.

An example of the RoHC-U description table (tsib14020) according to thepresent invention is illustrated. As described in the foregoing, theRoHC-U adaptation module may generate information related to headercompression.

signaling_type can be an 8-bit field that indicates the type ofsignaling carried by this table. The value of signaling_type field forROHC-U description table (RDT) can be set to “0x02.”

PLP_ID can be an 8-bit field that indicates the PLP corresponding tothis table.

context_id can be an 8-bit field that indicates the context id (CID) ofthe compressed IP stream. In this system, 8-bit CID can be used forlarge CID.

context_profile can be an 8-bit field that indicates the range ofprotocols used to compress the stream. This field can be omitted.

adaptation_mode can be a 2-bit field that indicates the mode ofadaptation module in this PLP. Adaptation modes have been describedabove.

context_config can be a 2-bit field that indicates the combination ofthe context information. If there is no context information in thistable, this field may be set to “0x0.” If the static_chain( ) ordynamic_chain( ) byte is included in this table, this field may be setto “0x01” or “0x02” respectively. If both of the static_chain( ) anddynamic_chain( ) byte are included in this table, this field may be setto “0x03.”

context_length can be an 8-bit field that indicates the length of thestatic chain byte sequence. This field can be omitted.

static_chain_byte ( ) can be a field that conveys the static informationused to initialize the ROHC-U decompressor. The size and structure ofthis field depend on the context profile.

dynamic_chain_byte ( ) can be a field that conveys the dynamicinformation used to initialize the ROHC-U decompressor. The size andstructure of this field depend on the context profile.

The static_chain_byte can be defined as sub-header information of IRpacket. The dynamic_chain_byte can be defined as sub-header informationof IR packet and IR-DYN packet.

FIG. 15 illustrates a structure of a link layer on a transmitter sideaccording to an embodiment of the present invention.

The present embodiment presumes that an IP packet is processed. From afunctional point of view, the link layer on the transmitter side maybroadly include a link layer signaling part in which signalinginformation is processed, an overhead reduction part, and/or anencapsulation part. In addition, the link layer on the transmitter sidemay include a scheduler for controlling and scheduling an overalloperation of the link layer and/or input and output parts of the linklayer.

First, signaling information of an upper layer and/or a system parametertsib15010 may be delivered to the link layer. In addition, an IP streamincluding IP packets may be delivered to the link layer from an IP layertsib15110.

As described above, the scheduler tsib15020 may determine and controloperations of several modules included in the link layer. The deliveredsignaling information and/or system parameter tsib15010 may be filtereror used by the scheduler tsib15020. Information, which corresponds to apart of the delivered signaling information and/or system parametertsib15010, necessary for a receiver may be delivered to the link layersignaling part. In addition, information, which corresponds to a part ofthe signaling information, necessary for an operation of the link layermay be delivered to an overhead reduction controller tsib15120 or anencapsulation controller tsib15180.

The link layer signaling part may collect information to be transmittedas a signal in a physical layer, and convert/configure the informationin a form suitable for transmission. The link layer signaling part mayinclude a signaling manager tsib15030, a signaling formatter tsib15040,and/or a buffer for channels tsib15050.

The signaling manager tsib15030 may receive signaling informationdelivered from the scheduler tsib15020 and/or signaling (and/or context)information delivered from the overhead reduction part. The signalingmanager tsib15030 may determine a path for transmission of the signalinginformation for delivered data. The signaling information may bedelivered through the path determined by the signaling managertsib15030. As described in the foregoing, signaling information to betransmitted through a divided channel such as the FIC, the EAS, etc. maybe delivered to the signaling formatter tsib15040, and other signalinginformation may be delivered to an encapsulation buffer tsib15070.

The signaling formatter tsib15040 may format related signalinginformation in a form suitable for each divided channel such thatsignaling information may be transmitted through a separately dividedchannel. As described in the foregoing, the physical layer may includeseparate physically/logically divided channels. The divided channels maybe used to transmit FIC signaling information or EAS-relatedinformation. The FIC or EAS-related information may be sorted by thesignaling manager tsib15030, and input to the signaling formattertsib15040. The signaling formatter tsib15040 may format the informationbased on each separate channel. When the physical layer is designed totransmit particular signaling information through a separately dividedchannel other than the FIC and the EAS, a signaling formatter for theparticular signaling information may be additionally provided. Throughthis scheme, the link layer may be compatible with various physicallayers.

The buffer for channels tsib15050 may deliver the signaling informationreceived from the signaling formatter tsib15040 to separate dedicatedchannels tsib15060. The number and content of the separate channels mayvary depending on embodiments.

As described in the foregoing, the signaling manager tsib15030 maydeliver signaling information, which is not delivered to a particularchannel, to the encapsulation buffer tsib15070. The encapsulation buffertsib15070 may function as a buffer that receives the signalinginformation which is not delivered to the particular channel.

An encapsulation block for signaling information tsib15080 mayencapsulate the signaling information which is not delivered to theparticular channel. A transmission buffer tsib15090 may function as abuffer that delivers the encapsulated signaling information to a DP forsignaling information tsib15100. Here, the DP for signaling informationtsib15100 may refer to the above-described PLS region.

The overhead reduction part may allow efficient transmission by removingoverhead of packets delivered to the link layer. It is possible toconfigure overhead reduction parts corresponding to the number of IPstreams input to the link layer.

An overhead reduction buffer tsib15130 may receive an IP packetdelivered from an upper layer. The received IP packet may be input tothe overhead reduction part through the overhead reduction buffertsib15130.

An overhead reduction controller tsib15120 may determine whether toperform overhead reduction on a packet stream input to the overheadreduction buffer tsib15130. The overhead reduction controller tsib15120may determine whether to perform overhead reduction for each packetstream. When overhead reduction is performed on a packet stream, packetsmay be delivered to a robust header compression (RoHC) compressortsib15140 to perform overhead reduction. When overhead reduction is notperformed on a packet stream, packets may be delivered to theencapsulation part to perform encapsulation without overhead reduction.Whether to perform overhead reduction of packets may be determined basedon the signaling information tsib15010 delivered to the link layer. Thesignaling information may be delivered to the encapsulation controllertsib15180 by the scheduler tsib15020.

The RoHC compressor tsib15140 may perform overhead reduction on a packetstream. The RoHC compressor tsib15140 may perform an operation ofcompressing a header of a packet. Various schemes may be used foroverhead reduction. Overhead reduction may be performed using a schemeproposed by the present invention. The present invention presumes an IPstream, and thus an expression “RoHC compressor” is used. However, thename may be changed depending on embodiments. The operation is notrestricted to compression of the IP stream, and overhead reduction ofall types of packets may be performed by the RoHC compressor tsib15140.

A packet stream configuration block tsib15150 may separate informationto be transmitted to a signaling region and information to betransmitted to a packet stream from IP packets having compressedheaders. The information to be transmitted to the packet stream mayrefer to information to be transmitted to a DP region. The informationto be transmitted to the signaling region may be delivered to asignaling and/or context controller tsib15160. The information to betransmitted to the packet stream may be transmitted to the encapsulationpart.

The signaling and/or context controller tsib15160 may collect signalingand/or context information and deliver the signaling and/or contextinformation to the signaling manager in order to transmit the signalingand/or context information to the signaling region.

The encapsulation part may perform an operation of encapsulating packetsin a form suitable for a delivery to the physical layer. It is possibleto configure encapsulation parts corresponding to the number of IPstreams.

An encapsulation buffer tsib15170 may receive a packet stream forencapsulation. Packets subjected to overhead reduction may be receivedwhen overhead reduction is performed, and an input IP packet may bereceived without change when overhead reduction is not performed.

An encapsulation controller tsib15180 may determine whether toencapsulate an input packet stream. When encapsulation is performed, thepacket stream may be delivered to a segmentation/concatenation blocktsib15190. When encapsulation is not performed, the packet stream may bedelivered to a transmission buffer tsib15230. Whether to encapsulatepackets may be determined based on the signaling information tsib15010delivered to the link layer. The signaling information may be deliveredto the encapsulation controller tsib15180 by the scheduler tsib15020.

In the segmentation/concatenation block tsib15190, the above-describedsegmentation or concatenation operation may be performed on packets. Inother words, when an input IP packet is longer than a link layer packetcorresponding to an output of the link layer, one IP packet may besegmented into several segments to configure a plurality of link layerpacket payloads. On the other hand, when an input IP packet is shorterthan a link layer packet corresponding to an output of the link layer,several IP packets may be concatenated to configure one link layerpacket payload.

A packet configuration table tsib15200 may have configurationinformation of a segmented and/or concatenated link layer packet. Atransmitter and a receiver may have the same information in the packetconfiguration table tsib15200. The transmitter and the receiver mayrefer to the information of the packet configuration table tsib15200. Anindex value of the information of the packet configuration tabletsib15200 may be included in a header of the link layer packet.

A link layer header information block tsib15210 may collect headerinformation generated in an encapsulation process. In addition, the linklayer header information block tsib15210 may collect header informationincluded in the packet configuration table tsib15200. The link layerheader information block tsib15210 may configure header informationaccording to a header structure of the link layer packet.

A header attachment block tsib15220 may add a header to a payload of asegmented and/or concatenated link layer packet. The transmission buffertsib15230 may function as a buffer to deliver the link layer packet to aDP tsib15240 of the physical layer.

The respective blocks, modules, or parts may be configured as onemodule/protocol or a plurality of modules/protocols in the link layer.

FIG. 16 illustrates a structure of a link layer on a receiver sideaccording to an embodiment of the present invention.

The present embodiment presumes that an IP packet is processed. From afunctional point of view, the link layer on the receiver side maybroadly include a link layer signaling part in which signalinginformation is processed, an overhead processing part, and/or adecapsulation part. In addition, the link layer on the receiver side mayinclude a scheduler for controlling and scheduling overall operation ofthe link layer and/or input and output parts of the link layer.

First, information received through a physical layer may be delivered tothe link layer. The link layer may process the information, restore anoriginal state before being processed at a transmitter side, and thendeliver the information to an upper layer. In the present embodiment,the upper layer may be an IP layer.

Information, which is separated in the physical layer and deliveredthrough a particular channel tsib16030, may be delivered to a link layersignaling part. The link layer signaling part may determine signalinginformation received from the physical layer, and deliver the determinedsignaling information to each part of the link layer.

A buffer for channels tsib16040 may function as a buffer that receivessignaling information transmitted through particular channels. Asdescribed in the foregoing, when physically/logically divided separatechannels are present in the physical layer, it is possible to receivesignaling information transmitted through the channels. When theinformation received from the separate channels is segmented, thesegmented information may be stored until complete information isconfigured.

A signaling decoder/parser tsib16050 may verify a format of thesignaling information received through the particular channel, andextract information to be used in the link layer. When the signalinginformation received through the particular channel is encoded, decodingmay be performed. In addition, according to a given embodiment, it ispossible to verify integrity, etc. of the signaling information.

A signaling manager tsib16060 may integrate signaling informationreceived through several paths. Signaling information received through aDP for signaling tsib16070 to be described below may be integrated inthe signaling manager tsib16060. The signaling manager tsib16060 maydeliver signaling information necessary for each part in the link layer.For example, the signaling manager tsib16060 may deliver contextinformation, etc. for recovery of a packet to the overhead processingpart. In addition, the signaling manager tsib16060 may deliver signalinginformation for control to a scheduler tsib16020.

General signaling information, which is not received through a separateparticular channel, may be received through the DP for signalingtsib16070. Here, the DP for signaling may refer to PLS, L1, etc. Here,the DP may be referred to as a PLP. A reception buffer tsib16080 mayfunction as a buffer that receives signaling information delivered fromthe DP for signaling. In a decapsulation block for signaling informationtsib16090, the received signaling information may be decapsulated. Thedecapsulated signaling information may be delivered to the signalingmanager tsib16060 through a decapsulation buffer tsib16100. As describedin the foregoing, the signaling manager tsib16060 may collate signalinginformation, and deliver the collated signaling information to anecessary part in the link layer.

The scheduler tsib16020 may determine and control operations of severalmodules included in the link layer. The scheduler tsib16020 may controleach part of the link layer using receiver information tsib16010 and/orinformation delivered from the signaling manager tsib16060. In addition,the scheduler tsib16020 may determine an operation mode, etc. of eachpart. Here, the receiver information tsib16010 may refer to informationpreviously stored in the receiver. The scheduler tsib16020 may useinformation changed by a user such as channel switching, etc. to performa control operation.

The decapsulation part may filter a packet received from a DP tsib16110of the physical layer, and separate a packet according to a type of thepacket. It is possible to configure decapsulation parts corresponding tothe number of DPs that can be simultaneously decoded in the physicallayer.

The decapsulation buffer tsib16100 may function as a buffer thatreceives a packet stream from the physical layer to performdecapsulation. A decapsulation controller tsib16130 may determinewhether to decapsulate an input packet stream. When decapsulation isperformed, the packet stream may be delivered to a link layer headerparser tsib16140. When decapsulation is not performed, the packet streammay be delivered to an output buffer tsib16220. The signalinginformation received from the scheduler tsib16020 may be used todetermine whether to perform decapsulation.

The link layer header parser tsib16140 may identify a header of thedelivered link layer packet. It is possible to identify a configurationof an IP packet included in a payload of the link layer packet byidentifying the header. For example, the IP packet may be segmented orconcatenated.

A packet configuration table tsib16150 may include payload informationof segmented and/or concatenated link layer packets. The transmitter andthe receiver may have the same information in the packet configurationtable tsib16150. The transmitter and the receiver may refer to theinformation of the packet configuration table tsib16150. It is possibleto find a value necessary for reassembly based on index informationincluded in the link layer packet.

A reassembly block tsib16160 may configure payloads of the segmentedand/or concatenated link layer packets as packets of an original IPstream. Segments may be collected and reconfigured as one IP packet, orconcatenated packets may be separated and reconfigured as a plurality ofIP packet streams. Recombined IP packets may be delivered to theoverhead processing part.

The overhead processing part may perform an operation of restoring apacket subjected to overhead reduction to an original packet as areverse operation of overhead reduction performed in the transmitter.This operation may be referred to as overhead processing. It is possibleto configure overhead processing parts corresponding to the number ofDPs that can be simultaneously decoded in the physical layer.

A packet recovery buffer tsib16170 may function as a buffer thatreceives a decapsulated RoHC packet or IP packet to perform overheadprocessing.

An overhead controller tsib16180 may determine whether to recover and/ordecompress the decapsulated packet. When recovery and/or decompressionare performed, the packet may be delivered to a packet stream recoveryblock tsib16190. When recovery and/or decompression are not performed,the packet may be delivered to the output buffer tsib16220. Whether toperform recovery and/or decompression may be determined based on thesignaling information delivered by the scheduler tsib16020.

The packet stream recovery block tsib16190 may perform an operation ofintegrating a packet stream separated from the transmitter with contextinformation of the packet stream. This operation may be a process ofrestoring a packet stream such that an RoHC decompressor tsib16210 canperform processing. In this process, it is possible to receive signalinginformation and/or context information from a signaling and/or contextcontroller tsib16200. The signaling and/or context controller tsib16200may determine signaling information delivered from the transmitter, anddeliver the signaling information to the packet stream recovery blocktsib16190 such that the signaling information may be mapped to a streamcorresponding to a context ID.

The RoHC decompressor tsib16210 may restore headers of packets of thepacket stream. The packets of the packet stream may be restored to formsof original IP packets through restoration of the headers. In otherwords, the RoHC decompressor tsib16210 may perform overhead processing.

The output buffer tsib16220 may function as a buffer before an outputstream is delivered to an IP layer tsib16230.

The link layers of the transmitter and the receiver proposed in thepresent invention may include the blocks or modules described above. Inthis way, the link layer may independently operate irrespective of anupper layer and a lower layer, overhead reduction may be efficientlyperformed, and a supportable function according to an upper/lower layermay be easily defined/added/deleted.

FIG. 17 illustrates a configuration of signaling transmission through alink layer according to an embodiment of the present invention(transmitting/receiving sides).

In the present invention, a plurality of service providers(broadcasters) may provide services within one frequency band. Inaddition, a service provider may provide a plurality of services, andone service may include one or more components. It can be consideredthat the user receives content using a service as a unit.

The present invention presumes that a transmission protocol based on aplurality of sessions is used to support an IP hybrid broadcast.Signaling information delivered through a signaling path may bedetermined based on a transmission configuration of each protocol.Various names may be applied to respective protocols according to agiven embodiment.

In the illustrated data configuration tsib17010 on the transmittingside, service providers (broadcasters) may provide a plurality ofservices (Service #1, #2, . . . ). In general, a signal for a servicemay be transmitted through a general transmission session (signaling C).However, the signal may be transmitted through a particular session(dedicated session) according to a given embodiment (signaling B).

Service data and service signaling information may be encapsulatedaccording to a transmission protocol. According to a given embodiment,an IP/UDP layer may be used. According to a given embodiment, a signalin the IP/UDP layer (signaling A) may be additionally provided. Thissignaling may be omitted.

Data processed using the IP/UDP may be input to the link layer. Asdescribed in the foregoing, overhead reduction and/or encapsulation maybe performed in the link layer. Here, link layer signaling may beadditionally provided. Link layer signaling may include a systemparameter, etc. Link layer signaling has been described above.

The service data and the signaling information subjected to the aboveprocess may be processed through PLPs in a physical layer. Here, a PLPmay be referred to as a DP. The example illustrated in the figurepresumes a case in which a base DP/PLP is used. However, depending onembodiments, transmission may be performed using only a general DP/PLPwithout the base DP/PLP.

In the example illustrated in the figure, a particular channel(dedicated channel) such as an FIC, an EAC, etc. is used. A signaldelivered through the FIC may be referred to as a fast information table(FIT), and a signal delivered through the EAC may be referred to as anemergency alert table (EAT). The FIT may be identical to theabove-described SLT. The particular channels may not be used dependingon embodiments. When the particular channel (dedicated channel) is notconfigured, the FIT and the EAT may be transmitted using a general linklayer signaling transmission scheme, or transmitted using a PLP via theIP/UDP as other service data.

According to a given embodiment, system parameters may include atransmitter-related parameter, a service provider-related parameter,etc. Link layer signaling may include IP header compression-relatedcontext information and/or identification information of data to whichthe context is applied. Signaling of an upper layer may include an IPaddress, a UDP number, service/component information, emergencyalert-related information, an IP/UDP address for service signaling, asession ID, etc. Detailed examples thereof have been described above.

In the illustrated data configuration tsib17020 on the receiving side,the receiver may decode only a PLP for a corresponding service usingsignaling information without having to decode all PLPs.

First, when the user selects or changes a service desired to bereceived, the receiver may be tuned to a corresponding frequency and mayread receiver information related to a corresponding channel stored in aDB, etc. The information stored in the DB, etc. of the receiver may beconfigured by reading an SLT at the time of initial channel scan.

After receiving the SLT and the information about the correspondingchannel, information previously stored in the DB is updated, andinformation about a transmission path of the service selected by theuser and information about a path, through which component informationis acquired or a signal necessary to acquire the information istransmitted, are acquired. When the information is not determined to bechanged using version information of the SLT, decoding or parsing may beomitted.

The receiver may verify whether SLT information is included in a PLP byparsing physical signaling of the PLP in a corresponding broadcaststream (not illustrated), which may be indicated through a particularfield of physical signaling. It is possible to access a position atwhich a service layer signal of a particular service is transmitted byaccessing the SLT information. The service layer signal may beencapsulated into the IP/UDP and delivered through a transmissionsession. It is possible to acquire information about a componentincluded in the service using this service layer signaling. A specificSLT-SLS configuration is as described above.

In other words, it is possible to acquire transmission path information,for receiving upper layer signaling information (service signalinginformation) necessary to receive the service, corresponding to one ofseveral packet streams and PLPs currently transmitted on a channel usingthe SLT. The transmission path information may include an IP address, aUDP port number, a session ID, a PLP ID, etc. Here, depending onembodiments, a value previously designated by the IANA or a system maybe used as an IP/UDP address. The information may be acquired using ascheme of accessing a DB or a shared memory, etc.

When the link layer signal and service data are transmitted through thesame PLP, or only one PLP is operated, service data delivered throughthe PLP may be temporarily stored in a device such as a buffer, etc.while the link layer signal is decoded.

It is possible to acquire information about a path through which theservice is actually transmitted using service signaling information of aservice to be received. In addition, a received packet stream may besubjected to decapsulation and header recovery using information such asoverhead reduction for a PLP to be received, etc.

In the illustrated example (tsib17020), the FIC and the EAC are used,and a concept of the base DP/PLP is presumed. As described in theforegoing, concepts of the FIC, the EAC, and the base DP/PLP may not beused.

While MISO or MIMO uses two antennas in the following for convenience ofdescription, the present invention is applicable to systems using two ormore antennas. The present invention proposes a physical profile (orsystem) optimized to minimize receiver complexity while attaining theperformance required for a particular use case. Physical (PHY) profiles(base, handheld and advanced profiles) according to an embodiment of thepresent invention are subsets of all configurations that a correspondingreceiver should implement. The PHY profiles share most of the functionalblocks but differ slightly in specific blocks and/or parameters. For thesystem evolution, future profiles may also be multiplexed with existingprofiles in a single radio frequency (RF) channel through a futureextension frame (FEF). The base profile and the handheld profileaccording to the embodiment of the present invention refer to profilesto which MIMO is not applied, and the advanced profile refers to aprofile to which MIMO is applied. The base profile may be used as aprofile for both the terrestrial broadcast service and the mobilebroadcast service. That is, the base profile may be used to define aconcept of a profile which includes the mobile profile. In addition, theadvanced profile may be divided into an advanced profile for a baseprofile with MIMO and an advanced profile for a handheld profile withMIMO. Moreover, the profiles may be changed according to intention ofthe designer.

The following terms and definitions may be applied to the presentinvention. The following terms and definitions may be changed accordingto design.

Auxiliary stream: sequence of cells carrying data of as yet undefinedmodulation and coding, which may be used for future extensions or asrequired by broadcasters or network operators

Base data pipe: data pipe that carries service signaling data

Baseband frame (or BBFRAME): set of Kbch bits which form the input toone FEC encoding process (BCH and LDPC encoding)

Cell: modulation value that is carried by one carrier of orthogonalfrequency division multiplexing (OFDM) transmission

Coded block: LDPC-encoded block of PLS1 data or one of the LDPC-encodedblocks of PLS2 data

Data pipe: logical channel in the physical layer that carries servicedata or related metadata, which may carry one or a plurality ofservice(s) or service component(s).

Data pipe unit (DPU): a basic unit for allocating data cells to a DP ina frame.

Data symbol: OFDM symbol in a frame which is not a preamble symbol (thedata symbol encompasses the frame signaling symbol and frame edgesymbol)

DP_ID: this 8-bit field identifies uniquely a DP within the systemidentified by the SYSTEM_ID

Dummy cell: cell carrying a pseudo-random value used to fill theremaining capacity not used for PLS signaling, DPs or auxiliary streams

Emergency alert channel (EAC): part of a frame that carries EASinformation data

Frame: physical layer time slot that starts with a preamble and endswith a frame edge symbol

Frame repetition unit: a set of frames belonging to the same ordifferent physical layer profiles including an FEF, which is repeatedeight times in a superframe

Fast information channel (FIC): a logical channel in a frame thatcarries mapping information between a service and the corresponding baseDP

FECBLOCK: set of LDPC-encoded bits of DP data

FFT size: nominal FFT size used for a particular mode, equal to theactive symbol period Ts expressed in cycles of an elementary period T

Frame signaling symbol: OFDM symbol with higher pilot density used atthe start of a frame in certain combinations of FFT size, guard intervaland scattered pilot pattern, which carries a part of the PLS data

Frame edge symbol: OFDM symbol with higher pilot density used at the endof a frame in certain combinations of FFT size, guard interval andscattered pilot pattern

Frame group: the set of all frames having the same PHY profile type in asuperframe

Future extension frame: physical layer time slot within the superframethat may be used for future extension, which starts with a preamble

Futurecast UTB system: proposed physical layer broadcast system, theinput of which is one or more MPEG2-TS, IP or general stream(s) and theoutput of which is an RF signal

Input stream: a stream of data for an ensemble of services delivered tothe end users by the system

Normal data symbol: data symbol excluding the frame signaling symbol andthe frame edge symbol

PHY profile: subset of all configurations that a corresponding receivershould implement

PLS: physical layer signaling data including PLS1 and PLS2

PLS1: a first set of PLS data carried in a frame signaling symbol (FSS)having a fixed size, coding and modulation, which carries basicinformation about a system as well as parameters needed to decode PLS2

NOTE: PLS1 data remains constant for the duration of a frame group

PLS2: a second set of PLS data transmitted in the FSS, which carriesmore detailed PLS data about the system and the DPs

PLS2 dynamic data: PLS2 data that dynamically changes frame-by-frame

PLS2 static data: PLS2 data that remains static for the duration of aframe group

Preamble signaling data: signaling data carried by the preamble symboland used to identify the basic mode of the system

Preamble symbol: fixed-length pilot symbol that carries basic PLS dataand is located at the beginning of a frame

The preamble symbol is mainly used for fast initial band scan to detectthe system signal, timing thereof, frequency offset, and FFT size.

Reserved for future use: not defined by the present document but may bedefined in future

Superframe: set of eight frame repetition units

Time interleaving block (TI block): set of cells within which timeinterleaving is carried out, corresponding to one use of a timeinterleaver memory

TI group: unit over which dynamic capacity allocation for a particularDP is carried out, made up of an integer, dynamically varying number ofXFECBLOCKs

NOTE: The TI group may be mapped directly to one frame or may be mappedto a plurality of frames. The TI group may contain one or more TIblocks.

Type 1 DP: DP of a frame where all DPs are mapped to the frame in timedivision multiplexing (TDM) scheme

Type 2 DP: DP of a frame where all DPs are mapped to the frame infrequency division multiplexing (FDM) scheme

XFECBLOCK: set of N_(cells) cells carrying all the bits of one LDPCFECBLOCK

FIG. 18 illustrates a configuration of a broadcast signal transmissionapparatus for future broadcast services according to an embodiment ofthe present invention.

The broadcast signal transmission apparatus for future broadcastservices according to the present embodiment may include an inputformatting block 1000, a bit interleaved coding & modulation (BICM)block 1010, a frame building block 1020, an OFDM generation block 1030and a signaling generation block 1040. Description will be given of anoperation of each block of the broadcast signal transmission apparatus.

In input data according to an embodiment of the present invention, IPstream/packets and MPEG2-TS may be main input formats, and other streamtypes are handled as general streams. In addition to these data inputs,management information is input to control scheduling and allocation ofthe corresponding bandwidth for each input stream. In addition, thepresent invention allows simultaneous input of one or a plurality of TSstreams, IP stream(s) and/or a general stream(s).

The input formatting block 1000 may demultiplex each input stream intoone or a plurality of data pipes, to each of which independent codingand modulation are applied. A DP is the basic unit for robustnesscontrol, which affects QoS. One or a plurality of services or servicecomponents may be carried by one DP. The DP is a logical channel in aphysical layer for delivering service data or related metadata capableof carrying one or a plurality of services or service components.

In addition, a DPU is a basic unit for allocating data cells to a DP inone frame.

An input to the physical layer may include one or a plurality of datastreams. Each of the data streams is delivered by one DP. The inputformatting block 1000 may covert a data stream input through one or morephysical paths (or DPs) into a baseband frame (BBF). In this case, theinput formatting block 1000 may perform null packet deletion or headercompression on input data (a TS or IP input stream) in order to enhancetransmission efficiency. A receiver may have a priori information for aparticular part of a header, and thus this known information may bedeleted from a transmitter. A null packet deletion block 3030 may beused only for a TS input stream.

In the BICM block 1010, parity data is added for error correction andencoded bit streams are mapped to complex-value constellation symbols.The symbols are interleaved across a specific interleaving depth that isused for the corresponding DP. For the advanced profile, MIMO encodingis performed in the BICM block 1010 and an additional data path is addedat the output for MIMO transmission.

The frame building block 1020 may map the data cells of the input DPsinto the OFDM symbols within a frame, and perform frequency interleavingfor frequency-domain diversity, especially to combat frequency-selectivefading channels. The frame building block 1020 may include a delaycompensation block, a cell mapper and a frequency interleaver.

The delay compensation block may adjust timing between DPs andcorresponding PLS data to ensure that the DPs and the corresponding PLSdata are co-timed at a transmitter side. The PLS data is delayed by thesame amount as the data pipes by addressing the delays of data pipescaused by the input formatting block and BICM block. The delay of theBICM block is mainly due to the time interleaver. In-band signaling datacarries information of the next TI group so that the information iscarried one frame ahead of the DPs to be signaled. The delaycompensation block delays in-band signaling data accordingly.

The cell mapper may map PLS, DPs, auxiliary streams, dummy cells, etc.to active carriers of the OFDM symbols in the frame. The basic functionof the cell mapper 7010 is to map data cells produced by the TIs foreach of the DPs, PLS cells, and EAC/FIC cells, if any, into arrays ofactive OFDM cells corresponding to each of the OFDM symbols within aframe. A basic function of the cell mapper is to map a data cellgenerated by time interleaving for each DP and PLS cell to an array ofactive OFDM cells (if present) corresponding to respective OFDM symbolsin one frame. Service signaling data (such as program specificinformation (PSI)/SI) may be separately gathered and sent by a DP. Thecell mapper operates according to dynamic information produced by ascheduler and the configuration of a frame structure. The frequencyinterleaver may randomly interleave data cells received from the cellmapper to provide frequency diversity. In addition, the frequencyinterleaver may operate on an OFDM symbol pair including two sequentialOFDM symbols using a different interleaving-seed order to obtain maximuminterleaving gain in a single frame.

The OFDM generation block 1030 modulates OFDM carriers by cells producedby the frame building block, inserts pilots, and produces a time domainsignal for transmission. In addition, this block subsequently insertsguard intervals, and applies peak-to-average power ratio (PAPR)reduction processing to produce a final RF signal.

Specifically, after inserting a preamble at the beginning of each frame,the OFDM generation block 1030 may apply conventional OFDM modulationhaving a cyclic prefix as a guard interval. For antenna space diversity,a distributed MISO scheme is applied across transmitters. In addition, aPAPR scheme is performed in the time domain. For flexible networkplanning, the present invention provides a set of various FFT sizes,guard interval lengths and corresponding pilot patterns.

In addition, the present invention may multiplex signals of a pluralityof broadcast transmission/reception systems in the time domain such thatdata of two or more different broadcast transmission/reception systemsproviding broadcast services may be simultaneously transmitted in thesame RF signal bandwidth. In this case, the two or more differentbroadcast transmission/reception systems refer to systems providingdifferent broadcast services. The different broadcast services may referto a terrestrial broadcast service, mobile broadcast service, etc.

The signaling generation block 1040 may create physical layer signalinginformation used for an operation of each functional block. Thissignaling information is also transmitted so that services of interestare properly recovered at a receiver side. Signaling informationaccording to an embodiment of the present invention may include PLSdata. PLS provides the receiver with a means to access physical layerDPs. The PLS data includes PLS1 data and PLS2 data.

The PLS1 data is a first set of PLS data carried in an FSS symbol in aframe having a fixed size, coding and modulation, which carries basicinformation about the system in addition to the parameters needed todecode the PLS2 data. The PLS1 data provides basic transmissionparameters including parameters required to enable reception anddecoding of the PLS2 data. In addition, the PLS1 data remains constantfor the duration of a frame group.

The PLS2 data is a second set of PLS data transmitted in an FSS symbol,which carries more detailed PLS data about the system and the DPs. ThePLS2 contains parameters that provide sufficient information for thereceiver to decode a desired DP. The PLS2 signaling further includes twotypes of parameters, PLS2 static data (PLS2-STAT data) and PLS2 dynamicdata (PLS2-DYN data). The PLS2 static data is PLS2 data that remainsstatic for the duration of a frame group and the PLS2 dynamic data isPLS2 data that dynamically changes frame by frame. Details of the PLSdata will be described later.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 19 illustrates a BICM block according to an embodiment of thepresent invention.

The BICM block illustrated in FIG. 19 corresponds to an embodiment ofthe BICM block 1010 described with reference to FIG. 18.

As described above, the broadcast signal transmission apparatus forfuture broadcast services according to the embodiment of the presentinvention may provide a terrestrial broadcast service, mobile broadcastservice, UHDTV service, etc.

Since QoS depends on characteristics of a service provided by thebroadcast signal transmission apparatus for future broadcast servicesaccording to the embodiment of the present invention, data correspondingto respective services needs to be processed using different schemes.Accordingly, the BICM block according to the embodiment of the presentinvention may independently process respective DPs by independentlyapplying SISO, MISO and MIMO schemes to data pipes respectivelycorresponding to data paths. Consequently, the broadcast signaltransmission apparatus for future broadcast services according to theembodiment of the present invention may control QoS for each service orservice component transmitted through each DP.

shows a BICM block applied to a profile (or system) to which MIMO is notapplied, and (b) shows a BICM block of a profile (or system) to whichMIMO is applied.

The BICM block to which MIMO is not applied and the BICM block to whichMIMO is applied may include a plurality of processing blocks forprocessing each DP.

Description will be given of each processing block of the BICM block towhich MIMO is not applied and the BICM block to which MIMO is applied.

A processing block 5000 of the BICM block to which MIMO is not appliedmay include a data FEC encoder 5010, a bit interleaver 5020, aconstellation mapper 5030, a signal space diversity (SSD) encoding block5040 and a time interleaver 5050.

The data FEC encoder 5010 performs FEC encoding on an input BBF togenerate FECBLOCK procedure using outer coding (BCH) and inner coding(LDPC). The outer coding (BCH) is optional coding method. A detailedoperation of the data FEC encoder 5010 will be described later.

The bit interleaver 5020 may interleave outputs of the data FEC encoder5010 to achieve optimized performance with a combination of LDPC codesand a modulation scheme while providing an efficiently implementablestructure. A detailed operation of the bit interleaver 5020 will bedescribed later.

The constellation mapper 5030 may modulate each cell word from the bitinterleaver 5020 in the base and the handheld profiles, or each cellword from the cell-word demultiplexer 5010-1 in the advanced profileusing either QPSK, QAM-16, non-uniform QAM (NUQ-64, NUQ-256, orNUQ-1024) or non-uniform constellation (NUC-16, NUC-64, NUC-256, orNUC-1024) mapping to give a power-normalized constellation point, e_(i).This constellation mapping is applied only for DPs. It is observed thatQAM-16 and NUQs are square shaped, while NUCs have arbitrary shapes.When each constellation is rotated by any multiple of 90 degrees, therotated constellation exactly overlaps with its original one. This“rotation-sense” symmetric property makes the capacities and the averagepowers of the real and imaginary components equal to each other. BothNUQs and NUCs are defined specifically for each code rate and theparticular one used is signaled by the parameter DP_MOD filed in thePLS2 data.

The time interleaver 5050 may operates at a DP level. Parameters of timeinterleaving (TI) may be set differently for each DP. A detailedoperation of the time interleaver 5050 will be described later.

A processing block 5000-1 of the BICM block to which MIMO is applied mayinclude the data FEC encoder, the bit interleaver, the constellationmapper, and the time interleaver.

However, the processing block 5000-1 is distinguished from theprocessing block 5000 of the BICM block to which MIMO is not applied inthat the processing block 5000-1 further includes a cell-worddemultiplexer 5010-1 and a MIMO encoding block 5020-1.

In addition, operations of the data FEC encoder, the bit interleaver,the constellation mapper, and the time interleaver in the processingblock 5000-1 correspond to those of the data FEC encoder 5010, the bitinterleaver 5020, the constellation mapper 5030, and the timeinterleaver 5050 described above, and thus description thereof isomitted.

The cell-word demultiplexer 5010-1 is used for a DP of the advancedprofile to divide a single cell-word stream into dual cell-word streamsfor MIMO processing.

The MIMO encoding block 5020-1 may process an output of the cell-worddemultiplexer 5010-1 using a MIMO encoding scheme. The MIMO encodingscheme is optimized for broadcast signal transmission. MIMO technologyis a promising way to obtain a capacity increase but depends on channelcharacteristics. Especially for broadcasting, a strong LOS component ofa channel or a difference in received signal power between two antennascaused by different signal propagation characteristics makes itdifficult to obtain capacity gain from MIMO. The proposed MIMO encodingscheme overcomes this problem using rotation-based precoding and phaserandomization of one of MIMO output signals.

MIMO encoding is intended for a 2×2 MIMO system requiring at least twoantennas at both the transmitter and the receiver. A MIMO encoding modeof the present invention may be defined as full-rate spatialmultiplexing (FR-SM). FR-SM encoding may provide capacity increase withrelatively small complexity increase at the receiver side. In addition,the MIMO encoding scheme of the present invention has no restriction onan antenna polarity configuration.

MIMO processing is applied at the DP level. NUQ (e_(1,i) and e_(2,i))corresponding to a pair of constellation mapper outputs is fed to aninput of a MIMO encoder. Paired MIMO encoder output (g1,i and g2,i) istransmitted by the same carrier k and OFDM symbol I of respective TXantennas thereof.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 20 illustrates a BICM block according to another embodiment of thepresent invention.

The BICM block illustrated in FIG. 20 corresponds to another embodimentof the BICM block 1010 described with reference to FIG. 18.

FIG. 20 illustrates a BICM block for protection of physical layersignaling (PLS), an emergency alert channel (EAC) and a fast informationchannel (FIC). The EAC is a part of a frame that carries EAS informationdata, and the FIC is a logical channel in a frame that carries mappinginformation between a service and a corresponding base DP. Details ofthe EAC and FIC will be described later.

Referring to FIG. 20, the BICM block for protection of the PLS, the EACand the FIC may include a PLS FEC encoder 6000, a bit interleaver 6010and a constellation mapper 6020.

In addition, the PLS FEC encoder 6000 may include a scrambler, a BCHencoding/zero insertion block, an LDPC encoding block and an LDPC paritypuncturing block. Description will be given of each block of the BICMblock.

The PLS FEC encoder 6000 may encode scrambled PLS 1/2 data, EAC and FICsections.

The scrambler may scramble PLS1 data and PLS2 data before BCH encodingand shortened and punctured LDPC encoding.

The BCH encoding/zero insertion block may perform outer encoding on thescrambled PLS 1/2 data using a shortened BCH code for PLS protection,and insert zero bits after BCH encoding. For PLS1 data only, output bitsof zero insertion may be permutted before LDPC encoding.

The LDPC encoding block may encode an output of the BCH encoding/zeroinsertion block using an LDPC code. To generate a complete coded block,C_(ldpc) and parity bits P_(ldpc) are encoded systematically from eachzero-inserted PLS information block I_(ldpc) and appended thereto.C _(ldpc)=[I _(ldpc) P _(ldpc)]=[i ₀ ,i ₁ , . . . i _(K_ldpc−1) ,p ₀ ,p₁ , . . . ,p _(N_ldpc−K_ldpc−1)]  [Equation 1]

The LDPC parity puncturing block may perform puncturing on the PLS1 dataand the PLS2 data.

When shortening is applied to PLS1 data protection, some LDPC paritybits are punctured after LDPC encoding. In addition, for PLS2 dataprotection, LDPC parity bits of PLS2 are punctured after LDPC encoding.These punctured bits are not transmitted.

The bit interleaver 6010 may interleave each of shortened and puncturedPLS1 data and PLS2 data.

The constellation mapper 6020 may map the bit-interleaved PLS1 data andPLS2 data to constellations.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 21 illustrates a bit interleaving process of PLS according to anembodiment of the present invention.

Each shortened and punctured PLS1 and PLS2 coded block is interleavedbit-by-bit as described in FIG. 22. Each block of additional parity bitsis interleaved with the same block interleaving structure butseparately.

In the case of BPSK, there are two branches for bit interleaving toduplicate FEC coded bits in the real and imaginary parts. Each codedblock is written to the upper branch first. The bits are mapped to thelower branch by applying modulo N_(FEC) addition with cyclic shiftingvalue floor(N_(FEC)/2), where N_(FEC) is the length of each LDPC codedblock after shortening and puncturing.

In other modulation cases, such as QSPK, QAM-16 and NUQ-64, FEC codedbits are written serially into the interleaver column-wise, where thenumber of columns is the same as the modulation order.

In the read operation, the bits for one constellation symbol are readout sequentially row-wise and fed into the bit demultiplexer block.These operations are continued until the end of the column.

Each bit interleaved group is demultiplexed bit-by-bit in a group beforeconstellation mapping. Depending on modulation order, there are twomapping rules. In the case of BPSK and QPSK, the reliability of bits ina symbol is equal. Therefore, the bit group read out from the bitinterleaving block is mapped to a QAM symbol without any operation.

In the cases of QAM-16 and NUQ-64 mapped to a QAM symbol, the rule ofoperation is described in FIG. 23(a). As shown in FIG. 23(a), i is bitgroup index corresponding to column index in bit interleaving.

FIG. 21 shows the bit demultiplexing rule for QAM-16. This operationcontinues until all bit groups are read from the bit interleaving block.

FIG. 22 illustrates a configuration of a broadcast signal receptionapparatus for future broadcast services according to an embodiment ofthe present invention.

The broadcast signal reception apparatus for future broadcast servicesaccording to the embodiment of the present invention may correspond tothe broadcast signal transmission apparatus for future broadcastservices described with reference to FIG. 18.

The broadcast signal reception apparatus for future broadcast servicesaccording to the embodiment of the present invention may include asynchronization & demodulation module 9000, a frame parsing module 9010,a demapping & decoding module 9020, an output processor 9030 and asignaling decoding module 9040. A description will be given of operationof each module of the broadcast signal reception apparatus.

The synchronization & demodulation module 9000 may receive input signalsthrough m Rx antennas, perform signal detection and synchronization withrespect to a system corresponding to the broadcast signal receptionapparatus, and carry out demodulation corresponding to a reverseprocedure of a procedure performed by the broadcast signal transmissionapparatus.

The frame parsing module 9010 may parse input signal frames and extractdata through which a service selected by a user is transmitted. If thebroadcast signal transmission apparatus performs interleaving, the frameparsing module 9010 may carry out deinterleaving corresponding to areverse procedure of interleaving. In this case, positions of a signaland data that need to be extracted may be obtained by decoding dataoutput from the signaling decoding module 9040 to restore schedulinginformation generated by the broadcast signal transmission apparatus.

The demapping & decoding module 9020 may convert input signals into bitdomain data and then deinterleave the same as necessary. The demapping &decoding module 9020 may perform demapping of mapping applied fortransmission efficiency and correct an error generated on a transmissionchannel through decoding. In this case, the demapping & decoding module9020 may obtain transmission parameters necessary for demapping anddecoding by decoding data output from the signaling decoding module9040.

The output processor 9030 may perform reverse procedures of variouscompression/signal processing procedures which are applied by thebroadcast signal transmission apparatus to improve transmissionefficiency. In this case, the output processor 9030 may acquirenecessary control information from data output from the signalingdecoding module 9040. An output of the output processor 9030 correspondsto a signal input to the broadcast signal transmission apparatus and maybe MPEG-TSs, IP streams (v4 or v6) and generic streams.

The signaling decoding module 9040 may obtain PLS information from asignal demodulated by the synchronization & demodulation module 9000. Asdescribed above, the frame parsing module 9010, the demapping & decodingmodule 9020 and the output processor 9030 may execute functions thereofusing data output from the signaling decoding module 9040.

A frame according to an embodiment of the present invention is furtherdivided into a number of OFDM symbols and a preamble. As shown in (d),the frame includes a preamble, one or more frame signaling symbols(FSSs), normal data symbols and a frame edge symbol (FES).

The preamble is a special symbol that enables fast futurecast UTB systemsignal detection and provides a set of basic transmission parameters forefficient transmission and reception of a signal. Details of thepreamble will be described later.

A main purpose of the FSS is to carry PLS data. For fast synchronizationand channel estimation, and hence fast decoding of PLS data, the FSS hasa dense pilot pattern than a normal data symbol. The FES has exactly thesame pilots as the FSS, which enables frequency-only interpolationwithin the FES and temporal interpolation, without extrapolation, forsymbols immediately preceding the FES.

FIG. 23 illustrates a signaling hierarchy structure of a frame accordingto an embodiment of the present invention.

FIG. 23 illustrates the signaling hierarchy structure, which is splitinto three main parts corresponding to preamble signaling data 11000,PLS1 data 11010 and PLS2 data 11020. A purpose of a preamble, which iscarried by a preamble symbol in every frame, is to indicate atransmission type and basic transmission parameters of the frame. PLS1enables the receiver to access and decode the PLS2 data, which containsthe parameters to access a DP of interest. PLS2 is carried in everyframe and split into two main parts corresponding to PLS2-STAT data andPLS2-DYN data. Static and dynamic portions of PLS2 data are followed bypadding, if necessary.

Preamble signaling data according to an embodiment of the presentinvention carries 21 bits of information that are needed to enable thereceiver to access PLS data and trace DPs within the frame structure.Details of the preamble signaling data are as follows.

FFT_SIZE: This 2-bit field indicates an FFT size of a current framewithin a frame group as described in the following Table 1.

TABLE 1 Value FFT size 00 8K FFT 01 16K FFT 10 32K FFT 11 Reserved

GI_FRACTION: This 3-bit field indicates a guard interval fraction valuein a current superframe as described in the following Table 2.

TABLE 2 Value GI_FRACTION 000 ⅕ 001 1/10 010 1/20 011 1/40 100 1/80 1011/160 110 to 111 Reserved

EAC_FLAG: This 1-bit field indicates whether the EAC is provided in acurrent frame. If this field is set to ‘1’, an emergency alert service(EAS) is provided in the current frame. If this field set to ‘0’, theEAS is not carried in the current frame. This field may be switcheddynamically within a superframe.

PILOT_MODE: This 1-bit field indicates whether a pilot mode is a mobilemode or a fixed mode for a current frame in a current frame group. Ifthis field is set to ‘0’, the mobile pilot mode is used. If the field isset to ‘1’, the fixed pilot mode is used.

PAPR_FLAG: This 1-bit field indicates whether PAPR reduction is used fora current frame in a current frame group. If this field is set to avalue of ‘1’, tone reservation is used for PAPR reduction. If this fieldis set to a value of ‘0’, PAPR reduction is not used.

RESERVED: This 7-bit field is reserved for future use.

FIG. 24 illustrates PLS1 data according to an embodiment of the presentinvention.

PLS1 data provides basic transmission parameters including parametersrequired to enable reception and decoding of PLS2. As mentioned above,the PLS1 data remain unchanged for the entire duration of one framegroup. A detailed definition of the signaling fields of the PLS1 data isas follows.

PREAMBLE_DATA: This 20-bit field is a copy of preamble signaling dataexcluding EAC_FLAG.

NUM_FRAME_FRU: This 2-bit field indicates the number of the frames perFRU.

PAYLOAD_TYPE: This 3-bit field indicates a format of payload datacarried in a frame group. PAYLOAD_TYPE is signaled as shown in Table 3.

TABLE 3 Value Payload type 1XX TS is transmitted. X1X IP stream istransmitted. XX1 GS is transmitted.

NUM_FSS: This 2-bit field indicates the number of FSSs in a currentframe.

SYSTEM_VERSION: This 8-bit field indicates a version of a transmittedsignal format. SYSTEM_VERSION is divided into two 4-bit fields: a majorversion and a minor version.

Major version: The MSB corresponding to four bits of the SYSTEM_VERSIONfield indicate major version information. A change in the major versionfield indicates a non-backward-compatible change. A default value is‘0000’. For a version described in this standard, a value is set to‘0000’.

Minor version: The LSB corresponding to four bits of SYSTEM_VERSIONfield indicate minor version information. A change in the minor versionfield is backwards compatible.

CELL_ID: This is a 16-bit field which uniquely identifies a geographiccell in an ATSC network. An ATSC cell coverage area may include one ormore frequencies depending on the number of frequencies used perfuturecast UTB system. If a value of CELL_ID is not known orunspecified, this field is set to ‘0’.

NETWORK_ID: This is a 16-bit field which uniquely identifies a currentATSC network.

SYSTEM_ID: This 16-bit field uniquely identifies the futurecast UTBsystem within the ATSC network. The futurecast UTB system is aterrestrial broadcast system whose input is one or more input streams(TS, IP, GS) and whose output is an RF signal. The futurecast UTB systemcarries one or more PHY profiles and FEF, if any. The same futurecastUTB system may carry different input streams and use different RFs indifferent geographical areas, allowing local service insertion. Theframe structure and scheduling are controlled in one place and areidentical for all transmissions within the futurecast UTB system. One ormore futurecast UTB systems may have the same SYSTEM_ID meaning thatthey all have the same physical layer structure and configuration.

The following loop includes FRU_PHY_PROFILE, FRU_FRAME_LENGTH,FRU_GI_FRACTION, and RESERVED which are used to indicate an FRUconfiguration and a length of each frame type. A loop size is fixed sothat four PHY profiles (including an FEF) are signaled within the FRU.If NUM_FRAME_FRU is less than 4, unused fields are filled with zeros.

FRU_PHY_PROFILE: This 3-bit field indicates a PHY profile type of an(i+1)^(th) (i is a loop index) frame of an associated FRU. This fielduses the same signaling format as shown in Table 8.

FRU_FRAME_LENGTH: This 2-bit field indicates a length of an (i+1)^(t)″frame of an associated FRU. Using FRU_FRAME_LENGTH together withFRU_GI_FRACTION, an exact value of a frame duration may be obtained.

FRU_GI_FRACTION: This 3-bit field indicates a guard interval fractionvalue of an (i+1)^(th) frame of an associated FRU. FRU_GI_FRACTION issignaled according to Table 7.

RESERVED: This 4-bit field is reserved for future use.

The following fields provide parameters for decoding the PLS2 data.

PLS2_FEC_TYPE: This 2-bit field indicates an FEC type used by PLS2protection. The FEC type is signaled according to Table 4. Details ofLDPC codes will be described later.

TABLE 4 Content PLS2 FEC type 00 4K-1/4 and 7K-3/10 LDPC codes 01 to 11Reserved

PLS2_MOD: This 3-bit field indicates a modulation type used by PLS2. Themodulation type is signaled according to Table 5.

TABLE 5 Value PLS2_MODE 000 BPSK 001 QPSK 010 QAM-16 011 NUQ-64 100 to111 Reserved

PLS2_SIZE_CELL: This 15-bit field indicates C_(total_partial_block), asize (specified as the number of QAM cells) of the collection of fullcoded blocks for PLS2 that is carried in a current frame group. Thisvalue is constant during the entire duration of the current frame group.

PLS2_STAT_SIZE_BIT: This 14-bit field indicates a size, in bits, ofPLS2-STAT for a current frame group. This value is constant during theentire duration of the current frame group.

PLS2_DYN_SIZE_BIT: This 14-bit field indicates a size, in bits, ofPLS2-DYN for a current frame group. This value is constant during theentire duration of the current frame group.

PLS2_REP_FLAG: This 1-bit flag indicates whether a PLS2 repetition modeis used in a current frame group. When this field is set to a value of‘1’, the PLS2 repetition mode is activated. When this field is set to avalue of ‘0’, the PLS2 repetition mode is deactivated.

PLS2_REP_SIZE_CELL: This 15-bit field indicates C_(total_partial_block),a size (specified as the number of QAM cells) of the collection ofpartial coded blocks for PLS2 carried in every frame of a current framegroup, when PLS2 repetition is used. If repetition is not used, a valueof this field is equal to 0. This value is constant during the entireduration of the current frame group.

PLS2_NEXT_FEC_TYPE: This 2-bit field indicates an FEC type used for PLS2that is carried in every frame of a next frame group. The FEC type issignaled according to Table 10.

PLS2_NEXT_MOD: This 3-bit field indicates a modulation type used forPLS2 that is carried in every frame of a next frame group. Themodulation type is signaled according to Table 11.

PLS2_NEXT_REP_FLAG: This 1-bit flag indicates whether the PLS2repetition mode is used in a next frame group. When this field is set toa value of ‘1’, the PLS2 repetition mode is activated. When this fieldis set to a value of ‘0’, the PLS2 repetition mode is deactivated.

PLS2_NEXT_REP_SIZE_CELL: This 15-bit field indicatesC_(total_full_block), a size (specified as the number of QAM cells) ofthe collection of full coded blocks for PLS2 that is carried in everyframe of a next frame group, when PLS2 repetition is used. If repetitionis not used in the next frame group, a value of this field is equal to0. This value is constant during the entire duration of a current framegroup.

PLS2_NEXT_REP_STAT_SIZE_BIT: This 14-bit field indicates a size, inbits, of PLS2-STAT for a next frame group. This value is constant in acurrent frame group.

PLS2_NEXT_REP_DYN_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-DYN for a next frame group. This value is constant ina current frame group.

PLS2_AP_MODE: This 2-bit field indicates whether additional parity isprovided for PLS2 in a current frame group. This value is constantduring the entire duration of the current frame group. Table 6 belowprovides values of this field. When this field is set to a value of‘00’, additional parity is not used for the PLS2 in the current framegroup.

TABLE 6 Value PLS2-AP mode 00 AP is not provided 01 AP1 mode 10 to 11Reserved

PLS2_AP_SIZE_CELL: This 15-bit field indicates a size (specified as thenumber of QAM cells) of additional parity bits of PLS2. This value isconstant during the entire duration of a current frame group.

PLS2_NEXT_AP_MODE: This 2-bit field indicates whether additional parityis provided for PLS2 signaling in every frame of a next frame group.This value is constant during the entire duration of a current framegroup. Table 12 defines values of this field.

PLS2_NEXT_AP_SIZE_CELL: This 15-bit field indicates a size (specified asthe number of QAM cells) of additional parity bits of PLS2 in everyframe of a next frame group. This value is constant during the entireduration of a current frame group.

RESERVED: This 32-bit field is reserved for future use.

CRC_32: A 32-bit error detection code, which is applied to all PLS1signaling.

FIG. 25 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 25 illustrates PLS2-STAT data of the PLS2 data. The PLS2-STAT datais the same within a frame group, while PLS2-DYN data providesinformation that is specific for a current frame.

Details of fields of the PLS2-STAT data are described below.

FIC_FLAG: This 1-bit field indicates whether the FIC is used in acurrent frame group. If this field is set to ‘1’, the FIC is provided inthe current frame. If this field set to ‘0’, the FIC is not carried inthe current frame. This value is constant during the entire duration ofa current frame group.

AUX_FLAG: This 1-bit field indicates whether an auxiliary stream is usedin a current frame group. If this field is set to ‘1’, the auxiliarystream is provided in a current frame. If this field set to ‘0’, theauxiliary stream is not carried in the current frame. This value isconstant during the entire duration of current frame group.

NUM_DP: This 6-bit field indicates the number of DPs carried within acurrent frame. A value of this field ranges from 1 to 64, and the numberof DPs is NUM_DP+1.

DP_ID: This 6-bit field identifies uniquely a DP within a PHY profile.

DP_TYPE: This 3-bit field indicates a type of a DP. This is signaledaccording to the following Table 7.

TABLE 7 Value DP Type 000 DP Type 1 001 DP Type 2 010 to 111 Reserved

DP_GROUP_ID: This 8-bit field identifies a DP group with which a currentDP is associated. This may be used by the receiver to access DPs ofservice components associated with a particular service having the sameDP_GROUP_ID.

BASE_DP_ID: This 6-bit field indicates a DP carrying service signalingdata (such as PSI/SI) used in a management layer. The DP indicated byBASE_DP_ID may be either a normal DP carrying the service signaling dataalong with service data or a dedicated DP carrying only the servicesignaling data.

DP_FEC_TYPE: This 2-bit field indicates an FEC type used by anassociated DP. The FEC type is signaled according to the following Table8.

TABLE 8 Value FEC_TYPE 00 16K LDPC 01 64K LDPC 10 to 11 Reserved

DP_COD: This 4-bit field indicates a code rate used by an associated DP.The code rate is signaled according to the following Table 9.

TABLE 9 Value Code rate 0000 5/15 0001 6/15 0010 7/15 0011 8/15 01009/15 0101 10/15  0110 11/15  0111 12/15  1000 13/15  1001 to 1111Reserved

DP_MOD: This 4-bit field indicates modulation used by an associated DP.The modulation is signaled according to the following Table 10.

TABLE 10 Value Modulation 0000 QPSK 0001 QAM-16 0010 NUQ-64 0011 NUQ-2560100 NUQ-1024 0101 NUC-16 0110 NUC-64 0111 NUC-256 1000 NUC-1024 1001 to1111 Reserved

DP_SSD_FLAG: This 1-bit field indicates whether an SSD mode is used inan associated DP. If this field is set to a value of ‘1’, SSD is used.If this field is set to a value of ‘0’, SSD is not used.

The following field appears only if PHY_PROFILE is equal to ‘010’, whichindicates the advanced profile:

DP_MIMO: This 3-bit field indicates which type of MIMO encoding processis applied to an associated DP. A type of MIMO encoding process issignaled according to the following Table 11.

TABLE 11 Value MIMO encoding 000 FR-SM 001 FRFD-SM 010 to 111 Reserved

DP_TI_TYPE: This 1-bit field indicates a type of time interleaving. Avalue of ‘0’ indicates that one TI group corresponds to one frame andcontains one or more TI blocks. A value of ‘1’ indicates that one TIgroup is carried in more than one frame and contains only one TI block.

DP_TI_LENGTH: The use of this 2-bit field (allowed values are only 1, 2,4, and 8) is determined by values set within the DP_TI_TYPE field asfollows.

If DP_TI_TYPE is set to a value of ‘1’, this field indicates P_(I), thenumber of frames to which each TI group is mapped, and one TI block ispresent per TI group (N_(TI)=1). Allowed values of P_(I) with the 2-bitfield are defined in Table 12 below.

If DP_TI_TYPE is set to a value of ‘0’, this field indicates the numberof TI blocks N_(TI) per TI group, and one TI group is present per frame(P_(I)=1). Allowed values of P_(i) with the 2-bit field are defined inthe following Table 12.

TABLE 12 2-bit field P_(I) N_(TI) 00 1 1 01 2 2 10 4 3 11 8 4

DP_FRAME_INTERVAL: This 2-bit field indicates a frame interval(I_(JUMP)) within a frame group for an associated DP and allowed valuesare 1, 2, 4, and 8 (the corresponding 2-bit field is ‘00’, ‘01’, ‘10’,or ‘11’, respectively). For DPs that do not appear every frame of theframe group, a value of this field is equal to an interval betweensuccessive frames. For example, if a DP appears on frames 1, 5, 9, 13,etc., this field is set to a value of ‘4’. For DPs that appear in everyframe, this field is set to a value of ‘1’.

DP_TI_BYPASS: This 1-bit field determines availability of the timeinterleaver 5050. If time interleaving is not used for a DP, a value ofthis field is set to ‘1’. If time interleaving is used, the value is setto ‘0’.

DP_FIRST_FRAME_IDX: This 5-bit field indicates an index of a first frameof a superframe in which a current DP occurs. A value ofDP_FIRST_FRAME_IDX ranges from 0 to 31.

DP_NUM_BLOCK_MAX: This 10-bit field indicates a maximum value ofDP_NUM_BLOCKS for this DP. A value of this field has the same range asDP_NUM_BLOCKS.

DP_PAYLOAD_TYPE: This 2-bit field indicates a type of payload datacarried by a given DP. DP_PAYLOAD_TYPE is signaled according to thefollowing Table 13.

TABLE 13 Value Payload type 00 TS 01 IP 10 GS 11 Reserved

DP_INBAND_MODE: This 2-bit field indicates whether a current DP carriesin-band signaling information. An in-band signaling type is signaledaccording to the following Table 14.

TABLE 14 Value In-band mode 00 In-band signaling is not carried. 01INBAND-PLS is carried 10 INBAND-ISSY is carried 11 INBAND-PLS andINBAND-ISSY are carried

DP_PROTOCOL_TYPE: This 2-bit field indicates a protocol type of apayload carried by a given DP. The protocol type is signaled accordingto Table 15 below when input payload types are selected.

TABLE 15 If If If DP_PAY- DP_PAY- DP_PAY- LOAD_TYPE LOAD_TYPE LOAD_TYPEValue is TS is IP is GS 00 MPEG2-TS IPv4 (Note) 01 Reserved IPv6Reserved 10 Reserved Reserved Reserved 11 Reserved Reserved Reserved

DP_CRC_MODE: This 2-bit field indicates whether CRC encoding is used inan input formatting block. A CRC mode is signaled according to thefollowing Table 16.

TABLE 16 Value CRC mode 00 Not used 01 CRC-8 10 CRC-16 11 CRC-32

DNP_MODE: This 2-bit field indicates a null-packet deletion mode used byan associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). DNP_MODE issignaled according to Table 17 below. If DP_PAYLOAD_TYPE is not TS(‘00’), DNP_MODE is set to a value of ‘00’.

TABLE 17 Value Null-packet deletion mode 00 Not used 01 DNP-NORMAL 10DNP-OFFSET 11 Reserved

ISSY_MODE: This 2-bit field indicates an ISSY mode used by an associatedDP when DP_PAYLOAD_TYPE is set to TS (‘00’). ISSY_MODE is signaledaccording to Table 18 below. If DP_PAYLOAD_TYPE is not TS (‘00’),ISSY_MODE is set to the value of ‘00’.

TABLE 18 Value ISSY mode 00 Not used 01 ISSY-UP 10 ISSY-BBF 11 Reserved

HC_MODE_TS: This 2-bit field indicates a TS header compression mode usedby an associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). HC_MODE_TSis signaled according to the following Table 19.

TABLE 19 Value Header compression mode 00 HC_MODE_TS 1 01 HC_MODE_TS 210 HC_MODE_TS 3 11 HC_MODE_TS 4

HC_MODE_IP: This 2-bit field indicates an IP header compression modewhen DP_PAYLOAD_TYPE is set to IP (‘01’). HC_MODE_IP is signaledaccording to the following Table 20.

TABLE 20 Value Header compression mode 00 No compression 01 HC_MODE_IP 110 to 11 Reserved

PID: This 13-bit field indicates the PID number for TS headercompression when DP_PAYLOAD_TYPE is set to TS (‘00’) and HC_MODE_TS isset to ‘01’ or ‘10’.

RESERVED: This 8-bit field is reserved for future use.

The following fields appear only if FIC_FLAG is equal to ‘1’.

FIC_VERSION: This 8-bit field indicates the version number of the FIC.

FIC_LENGTH_BYTE: This 13-bit field indicates the length, in bytes, ofthe FIC.

RESERVED: This 8-bit field is reserved for future use.

The following fields appear only if AUX_FLAG is equal to ‘1’.

NUM_AUX: This 4-bit field indicates the number of auxiliary streams.Zero means no auxiliary stream is used.

AUX_CONFIG_RFU: This 8-bit field is reserved for future use.

AUX_STREAM_TYPE: This 4-bit is reserved for future use for indicating atype of a current auxiliary stream.

AUX_PRIVATE_CONFIG: This 28-bit field is reserved for future use forsignaling auxiliary streams.

FIG. 26 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 26 illustrates PLS2-DYN data of the PLS2 data. Values of thePLS2-DYN data may change during the duration of one frame group whilesizes of fields remain constant.

Details of fields of the PLS2-DYN data are as below.

FRAME_INDEX: This 5-bit field indicates a frame index of a current framewithin a superframe. An index of a first frame of the superframe is setto ‘0’.

PLS_CHANGE_COUNTER: This 4-bit field indicates the number of superframesbefore a configuration changes. A next superframe with changes in theconfiguration is indicated by a value signaled within this field. Ifthis field is set to a value of ‘0000’, it means that no scheduledchange is foreseen. For example, a value of ‘1’ indicates that there isa change in the next superframe.

FIC_CHANGE_COUNTER: This 4-bit field indicates the number of superframesbefore a configuration (i.e., content of the FIC) changes. A nextsuperframe with changes in the configuration is indicated by a valuesignaled within this field. If this field is set to a value of ‘0000’,it means that no scheduled change is foreseen. For example, a value of‘0001’ indicates that there is a change in the next superframe.

RESERVED: This 16-bit field is reserved for future use.

The following fields appear in a loop over NUM_DP, which describeparameters associated with a DP carried in a current frame.

DP_ID: This 6-bit field uniquely indicates a DP within a PHY profile.

DP_START: This 15-bit (or 13-bit) field indicates a start position ofthe first of the DPs using a DPU addressing scheme. The DP_START fieldhas differing length according to the PHY profile and FFT size as shownin the following Table 21.

TABLE 21 DP_START field size PHY profile 64K 16K Base 13 bits 15 bitsHandheld — 13 bits Advanced 13 bits its

DP_NUM_BLOCK: This 10-bit field indicates the number of FEC blocks in acurrent TI group for a current DP. A value of DP_NUM_BLOCK ranges from 0to 1023.

RESERVED: This 8-bit field is reserved for future use.

The following fields indicate FIC parameters associated with the EAC.

EAC_FLAG: This 1-bit field indicates the presence of the EAC in acurrent frame. This bit is the same value as EAC_FLAG in a preamble.

EAS_WAKE_UP_VERSION_NUM: This 8-bit field indicates a version number ofa wake-up indication.

If the EAC_FLAG field is equal to ‘1’, the following 12 bits areallocated to EAC_LENGTH_BYTE.

If the EAC_FLAG field is equal to ‘0’, the following 12 bits areallocated to EAC_COUNTER.

EAC_LENGTH_BYTE: This 12-bit field indicates a length, in bytes, of theEAC.

EAC_COUNTER: This 12-bit field indicates the number of frames before aframe where the EAC arrives.

The following fields appear only if the AUX_FLAG field is equal to ‘1’.

AUX_PRIVATE_DYN: This 48-bit field is reserved for further use forsignaling auxiliary streams. A meaning of this field depends on a valueof AUX_STREAM_TYPE in a configurable PLS2-STAT.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS2.

FIG. 27 illustrates a logical structure of a frame according to anembodiment of the present invention.

As above mentioned, the PLS, EAC, FIC, DPs, auxiliary streams and dummycells are mapped to the active carriers of OFDM symbols in a frame. PLS1and PLS2 are first mapped to one or more FSSs. Thereafter, EAC cells, ifany, are mapped to an immediately following PLS field, followed next byFIC cells, if any. The DPs are mapped next after the PLS or after theEAC or the FIC, if any. Type 1 DPs are mapped first and Type 2 DPs aremapped next. Details of types of the DPs will be described later. Insome cases, DPs may carry some special data for EAS or service signalingdata. The auxiliary streams or streams, if any, follow the DPs, which inturn are followed by dummy cells. When the PLS, EAC, FIC, DPs, auxiliarystreams and dummy data cells are mapped all together in the abovementioned order, i.e. the PLS, EAC, FIC, DPs, auxiliary streams anddummy data cells, cell capacity in the frame is exactly filled.

FIG. 28 illustrates PLS mapping according to an embodiment of thepresent invention.

PLS cells are mapped to active carriers of FSS(s). Depending on thenumber of cells occupied by PLS, one or more symbols are designated asFSS(s), and the number of FSS(s) N_(FSS) is signaled by NUM_FSS in PLS1.The FSS is a special symbol for carrying PLS cells. Since robustness andlatency are critical issues in the PLS, the FSS(s) have higher pilotdensity, allowing fast synchronization and frequency-only interpolationwithin the FSS.

PLS cells are mapped to active carriers of the FSS(s) in a top-downmanner as shown in the figure. PLS1 cells are mapped first from a firstcell of a first FSS in increasing order of cell index. PLS2 cells followimmediately after a last cell of PLS1 and mapping continues downwarduntil a last cell index of the first FSS. If the total number ofrequired PLS cells exceeds the number of active carriers of one FSS,mapping proceeds to a next FSS and continues in exactly the same manneras the first FSS.

After PLS mapping is completed, DPs are carried next. If an EAC, an FICor both are present in a current frame, the EAC and the FIC are placedbetween the PLS and “normal” DPs.

Hereinafter, description will be given of encoding an FEC structureaccording to an embodiment of the present invention. As above mentioned,the data FEC encoder may perform FEC encoding on an input BBF togenerate an FECBLOCK procedure using outer coding (BCH), and innercoding (LDPC). The illustrated FEC structure corresponds to theFECBLOCK. In addition, the FECBLOCK and the FEC structure have samevalue corresponding to a length of an LDPC codeword.

As described above, BCH encoding is applied to each BBF (K_(bch) bits),and then LDPC encoding is applied to BCH-encoded BBF (K_(ldpc)bits=N_(bch) bits).

A value of N_(ldpc) is either 64,800 bits (long FECBLOCK) or 16,200 bits(short FECBLOCK).

Table 22 and Table 23 below show FEC encoding parameters for the longFECBLOCK and the short FECBLOCK, respectively.

TABLE 22 BCH error correction LDPC rate N_(ldpc) K_(ldpc) K_(bch)capability N_(bch) − K_(bch) 5/15 64800 21600 21408 12 192 6/15 2592025728 7/15 30240 30048 8/15 34560 34368 9/15 38880 38688 10/15  4320043008 11/15  47520 47328 12/15  51840 51648 13/15  56160 55968

TABLE 23 BCH error correction LDPC rate N_(ldpc) K_(ldpc) K_(bch)capability N_(bch) − K_(bch) 5/15 16200 5400 5232 12 168 6/15 6480 63127/15 7560 7392 8/15 8640 8472 9/15 9720 9552 10/15  10800 10632 11/15 11880 11712 12/15  12960 12792 13/15  14040 13872

Detailed operations of BCH encoding and LDPC encoding are as below.

A 12-error correcting BCH code is used for outer encoding of the BBF. ABCH generator polynomial for the short FECBLOCK and the long FECBLOCKare obtained by multiplying all polynomials together.

LDPC code is used to encode an output of outer BCH encoding. To generatea completed B_(ldpc) (FECBLOCK), P_(ldpc) (parity bits) is encodedsystematically from each I_(ldpc) (BCH—encoded BBF), and appended toI_(ldpc). The completed B_(ldpc) (FECBLOCK) is expressed by thefollowing Equation.B _(ldpc)=[I _(ldpc) P _(ldpc)]=[i ₀ ,i ₁ , . . . ,i _(K_ldpc−1) ,p ₀ ,p₁ , . . . ,p _(N) _(ldpc) _(−K) _(ldpc) ⁻¹]  [Equation 2]

Parameters for the long FECBLOCK and the short FECBLOCK are given in theabove Tables 22 and 23, respectively.

A detailed procedure to calculate N_(ldpc)−K_(ldpc) parity bits for thelong FECBLOCK, is as follows.

Initialize the parity bitsp ₀ =p ₁ =p ₂ = . . . =p _(N) _(ldpc) _(−K) _(ldpc) ⁻¹⁼0  [Equation 3]

2) Accumulate a first information bit—i₀, at a parity bit addressspecified in a first row of addresses of a parity check matrix. Detailsof the addresses of the parity check matrix will be described later. Forexample, for the rate of 13/15,

$\quad\begin{matrix}\begin{matrix}{p_{983} = {p_{983} \oplus i_{0}}} & {p_{2815} = {p_{2815} \oplus i_{0}}} \\{p_{4837} = {p_{4837} \oplus i_{0}}} & {p_{4989} = {p_{4989} \oplus i_{0}}} \\{p_{6138} = {p_{6138} \oplus i_{0}}} & {p_{6458} = {p_{6458} \oplus i_{0}}} \\{p_{6921} = {p_{6921} \oplus i_{0}}} & {p_{6974} = {p_{6974} \oplus i_{0}}} \\{p_{7572} = {p_{7572} \oplus i_{0}}} & {p_{8260} = {p_{8260} \oplus i_{0}}} \\{p_{8496} = {p_{8496} \oplus i_{0}}} & \;\end{matrix} & \lbrack {{Equation}\mspace{14mu} 4} \rbrack\end{matrix}$

3) For the next 359 information bits, i_(s), s=1, 2, . . . , 359,accumulate i_(s) at parity bit addresses using following Equation.{x+(s mod 360)×Q _(ldpc)} mod(N _(ldpc) −K _(ldpc))  [Equation 5]

Here, x denotes an address of a parity bit accumulator corresponding toa first bit i₀, and Q_(ldpc) is a code rate dependent constant specifiedin the addresses of the parity check matrix. Continuing with theexample, Q_(ldpc)=24 for the rate of 13/15, so for an information biti₁, the following operations are performed.

$\quad\begin{matrix}\begin{matrix}{p_{1007} = {p_{1007} \oplus i_{1}}} & {p_{2839} = {p_{2839} \oplus i_{1}}} \\{p_{4861} = {p_{4861} \oplus i_{1}}} & {p_{5013} = {p_{5013} \oplus i_{1}}} \\{p_{6162} = {p_{6162} \oplus i_{1}}} & {p_{6482} = {p_{6482} \oplus i_{1}}} \\{p_{6945} = {p_{6945} \oplus i_{1}}} & {p_{6998} = {p_{6998} \oplus i_{1}}} \\{p_{7596} = {p_{7596} \oplus i_{1}}} & {p_{8284} = {p_{8284} \oplus i_{1}}} \\{p_{8520} = {p_{8520} \oplus i_{1}}} & \;\end{matrix} & \lbrack {{Equation}\mspace{14mu} 6} \rbrack\end{matrix}$

4) For a 361th information bit i₃₆₀, an address of the parity bitaccumulator is given in a second row of the addresses of the paritycheck matrix. In a similar manner, addresses of the parity bitaccumulator for the following 359 information bits i_(s), s=361, 362, .. . , 719 are obtained using Equation 6, where x denotes an address ofthe parity bit accumulator corresponding to the information bit i₃₆₀,i.e., an entry in the second row of the addresses of the parity checkmatrix.

5) In a similar manner, for every group of 360 new information bits, anew row from the addresses of the parity check matrix is used to findthe address of the parity bit accumulator.

After all of the information bits are exhausted, a final parity bit isobtained as below.

6) Sequentially perform the following operations starting with i=1.p _(i) =p _(i) ⊕p _(i-1) ,i=1,2, . . . ,N _(ldpc) −K_(ldpc)−1  [Equation 7]

Here, final content of p_(i)=0, 1, . . . , N_(ldpc)−K_(ldpc)−1) is equalto a parity bit p_(i).

TABLE 24 Code rate Q_(ldpc) 5/15 120 6/15 108 7/15 96 8/15 84 9/15 7210/15  60 11/15  48 12/15  36 13/15  24

This LDPC encoding procedure for the short FECBLOCK is in accordancewith t LDPC encoding procedure for the long FECBLOCK, except that Table24 is replaced with Table 25, and the addresses of the parity checkmatrix for the long FECBLOCK are replaced with the addresses of theparity check matrix for the short FECBLOCK.

TABLE 25 Code rate Q_(ldpc) 5/15 30 6/15 27 7/15 24 8/15 21 9/15 1810/15  15 11/15  12 12/15  9 13/15  6

FIG. 29 illustrates time interleaving according to an embodiment of thepresent invention.

to (c) show examples of a TI mode.

A time interleaver operates at the DP level. Parameters of timeinterleaving (TI) may be set differently for each DP.

The following parameters, which appear in part of the PLS2-STAT data,configure the TI.

DP_TI_TYPE (allowed values: 0 or 1): This parameter represents the TImode. The value of ‘0’ indicates a mode with multiple TI blocks (morethan one TI block) per TI group. In this case, one TI group is directlymapped to one frame (no inter-frame interleaving). The value of ‘1’indicates a mode with only one TI block per TI group. In this case, theTI block may be spread over more than one frame (inter-frameinterleaving).

DP_TI_LENGTH: If DP_TI_TYPE=‘0’, this parameter is the number of TIblocks N_(TI) per TI group. For DP_TI_TYPE=‘1’, this parameter is thenumber of frames P_(I) spread from one TI group.

DP_NUM_BLOCK_MAX (allowed values: 0 to 1023): This parameter representsthe maximum number of XFECBLOCKs per TI group.

DP_FRAME_INTERVAL (allowed values: 1, 2, 4, and 8): This parameterrepresents the number of the frames I_(JUMP) between two successiveframes carrying the same DP of a given PHY profile.

DP_TI_BYPASS (allowed values: 0 or 1): If time interleaving is not usedfor a DP, this parameter is set to ‘1’. This parameter is set to ‘0’ iftime interleaving is used.

Additionally, the parameter DP_NUM_BLOCK from the PLS2-DYN data is usedto represent the number of XFECBLOCKs carried by one TI group of the DP.

When time interleaving is not used for a DP, the following TI group,time interleaving operation, and TI mode are not considered. However,the delay compensation block for the dynamic configuration informationfrom the scheduler may still be required. In each DP, the XFECBLOCKsreceived from SSD/MIMO encoding are grouped into TI groups. That is,each TI group is a set of an integer number of XFECBLOCKs and contains adynamically variable number of XFECBLOCKs. The number of XFECBLOCKs inthe TI group of index n is denoted by N_(xBLOCK_Group)(n) and issignaled as DP_NUM_BLOCK in the PLS2-DYN data. Note thatN_(xBLOCK_Group)(n) may vary from a minimum value of 0 to a maximumvalue of N_(xBLOCK_Group_MAX) (corresponding to DP_NUM_BLOCK_MAX), thelargest value of which is 1023.

Each TI group is either mapped directly to one frame or spread overP_(I) frames. Each TI group is also divided into more than one TI block(N_(TI)), where each TI block corresponds to one usage of a timeinterleaver memory. The TI blocks within the TI group may containslightly different numbers of XFECBLOCKs. If the TI group is dividedinto multiple TI blocks, the TI group is directly mapped to only oneframe. There are three options for time interleaving (except an extraoption of skipping time interleaving) as shown in the following Table26.

TABLE 26 Modes Descriptions Option 1 Each TI group contains one TI blockand is mapped directly to one frame as shown in (a). This option issignaled in PLS2-STAT by DP_TI_TYPE = ‘0’ and DP_TI_LENGTH = ‘1’ (N_(TI)= 1). Option 2 Each TI group contains one TI block and is mapped to morethan one frame. (b) shows an example, where one TI group is mapped totwo frames, i.e., DP_TI_LENGTH = ‘2’ (P_(I) = 2) and DP_FRAME_INTERVAL(I_(JUMP) = 2). This provides greater time diversity for low data-rateservices. This option is signaled in PLS2-STAT by DP_TI_TYPE = ‘1’.Option 3 Each TI group is divided into multiple TI blocks and is mappeddirectly to one frame as shown in (c). Each TI block may use a full TImemory so as to provide a maximum bit-rate for a DP. This option issignaled in PLS2-STAT by DP_TI_TYPE = ‘0’ and DP_TI_LENGTH = N_(TI),while P_(I) = 1.

Typically, the time interleaver may also function as a buffer for DPdata prior to a process of frame building. This is achieved by means oftwo memory banks for each DP. A first TI block is written to a firstbank. A second TI block is written to a second bank while the first bankis being read from and so on.

The TI is a twisted row-column block interleaver. For an s^(th) TI blockof an n^(th) TI group, the number of rows N_(r) of a TI memory is equalto the number of cells N_(cells), i.e., N_(r)=N_(cells) while the numberof columns N_(c) is equal to the number N_(xBLOCK_TI)(n,s).

FIG. 30 illustrates a basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention.

FIG. 30(a) shows a write operation in the time interleaver and FIG.30(b) shows a read operation in the time interleaver. A first XFECBLOCKis written column-wise into a first column of a TI memory, and a secondXFECBLOCK is written into a next column, and so on as shown in (a).Then, in an interleaving array, cells are read diagonal-wise. Duringdiagonal-wise reading from a first row (rightwards along a row beginningwith a left-most column) to a last row, N_(r) cells are read out asshown in (b). In detail, assuming z_(n,s,i) (i=0, . . . N_(r)N_(c)) as aTI memory cell position to be read sequentially, a reading process insuch an interleaving array is performed by calculating a row indexR_(n,s,i), a column index C_(n,s,i), and an associated twistingparameter T_(n,s,i) as in the following Equation.

  [Equation 8] GENERATE(R_(n,s,i),C_(n,s,i))= { R_(n,s,i) =mod(i,N_(r)), T_(n,s,i) = mod(S_(shift) × R_(n,s,i), N_(c)),$C_{n,s,i} = {{mod}\mspace{11mu}( {{T_{n,s,i} + \lfloor \frac{1}{N_{r}} \rfloor},N_{c}} )}$}

Here, S_(shift) is a common shift value for a diagonal-wise readingprocess regardless of N_(xBLOCK_TI)(n,s), and the shift value isdetermined by N_(xBLOCK_TI_MAX) given in PLS2-STAT as in the followingEquation.

$\begin{matrix}{{f{or}}\{ {\begin{matrix}{{{N^{\prime}}_{{{xBLOCK}\_{TI}}{\_{MAX}}} = {N_{{{xBLOCK}\_{TI}}{\_{MAX}}} + 1}},} & {{{if}\mspace{14mu} N_{{{xBLOCK}\_{TI}}{\_{MAX}}}{mod2}} = 0} \\{{N_{{xBLOCK}\mspace{11mu}{TI}\mspace{11mu}{MAX}}^{\prime} = N_{{xBLOCK}\mspace{11mu}{TI}\mspace{11mu}{MAX}}},} & {{{if}\mspace{14mu} N_{{xBLOCK}\mspace{11mu}{TI}\mspace{11mu}{MAX}}{mod2}} = 1}\end{matrix},{S_{shift} = \frac{{N^{\prime}}_{{{xBLOCK}\_{TI}}{\_{MAX}}} - 1}{2}}} } & \lbrack {{Equation}\mspace{14mu} 9} \rbrack\end{matrix}$

As a result, cell positions to be read are calculated by coordinatesz_(n,s,i)=N_(r)C_(n,s,i)+R_(n s,i).

FIG. 31 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

More specifically, FIG. 31 illustrates an interleaving array in a TImemory for each TI group, including virtual XFECBLOCKs whenN_(xBLOCK_TI)(0,0)=3, N_(xBLOCK_TI)(1,0)=6, and N_(xBLOCK_TI)(2,0)=5.

A variable number N_(xBLOCK_TI)(n,s)=N_(r) may be less than or equal toN_(xBLOCK_TI_MAX). Thus, in order to achieve single-memorydeinterleaving at a receiver side regardless of N_(xBLOCK_TI)(n,s), theinterleaving array for use in the twisted row-column block interleaveris set to a size of N_(r)×N_(c)=N_(cells)×N′_(xBLOCK_TI_MAX) byinserting the virtual XFECBLOCKs into the TI memory and a readingprocess is accomplished as in the following Equation.

[Equation 10] p = 0;  for i = 0;i < N_(cells)N_(xBLOCK) _(—) _(TI) _(—)_(MAX)′;i = i + 1  {GENERATE (R_(n,s,i),C_(n,s,i));  V_(i) =N_(r)C_(n,s,j) + R_(n,s,j)   if V_(i) < N_(cells)N_(xBLOCK TI)(n,s)   {   Z_(n,s,p) = V_(i); p = p + 1;    } }

The number of TI groups is set to 3. An option of the time interleaveris signaled in the PLS2-STAT data by DP_TI_TYPE=‘0’,DP_FRAME_INTERVAL=‘1’, and DP_TI_LENGTH=‘1’, i.e., NTI=1, IJUMP=1, andPI=1. The number of XFECBLOCKs, each of which has Ncells=30 cells, perTI group is signaled in the PLS2-DYN data by NxBLOCK_TI(0,0)=3,NxBLOCK_TI(1,0)=6, and NxBLOCK_TI(2,0)=5, respectively. A maximum numberof XFECBLOCKs is signaled in the PLS2-STAT data by NxBLOCK_Group_MAX,which leads to └N_(xBLOCK_Group_MAX)/N_(TI) ┘=N_(xBLOCK_TI_MAX)=6.

The purpose of the Frequency Interleaver, which operates on datacorresponding to a single OFDM symbol, is to provide frequency diversityby randomly interleaving data cells received from the frame builder. Inorder to get maximum interleaving gain in a single frame, a differentinterleaving-sequence is used for every OFDM symbol pair comprised oftwo sequential OFDM symbols.

Therefore, the frequency interleaver according to the present embodimentmay include an interleaving address generator for generating aninterleaving address for applying corresponding data to a symbol pair.

FIG. 32 illustrates an interleaving address generator including a mainpseudo-random binary sequence (PRBS) generator and a sub-PRBS generatoraccording to each FFT mode according to an embodiment of the presentinvention.

shows the block diagrams of the interleaving-address generator for 8KFFT mode, (b) shows the block diagrams of the interleaving-addressgenerator for 16K FFT mode and (c) shows the block diagrams of theinterleaving-address generator for 32K FFT mode.

The interleaving process for the OFDM symbol pair is described asfollows, exploiting a single interleaving-sequence. First, availabledata cells (the output cells from the Cell Mapper) to be interleaved inone OFDM symbol O_(m,l) is defined as O_(m,i)=└x_(m,l,0), . . . ,x_(m,l,p), . . . , x_(m,l,N) _(data) ⁻¹┘ for l=0, . . . , N_(sym)−1,where x_(m,l,p) is the p^(th) cell of the l^(th) OFDM symbol in them^(th) frame and N_(data) is the number of data cells: N_(data)=C_(FSS)for the frame signaling symbol(s), N_(data)=C_(data) for the normaldata, and N_(data)=C_(FES) for the frame edge symbol. In addition, theinterleaved data cells are defined as P_(m,l)=[v_(m,l,0), . . .,v_(m,l,N) _(data) ⁻¹] for l=0, . . . ,N_(sym)−1.

For the OFDM symbol pair, the interleaved OFDM symbol pair is given byv_(m,l,H,(p))=x_(m,l,p), p=0, . . . N_(data)−1, for the first OFDMsymbol of each pair v_(m,l,p)=x_(m,l,H) _(l) _((p)), p=0, . . .,N_(data)−1, for the second OFDM symbol of each pair, where H_(l)(p) isthe interleaving address generated by a PRBS generator.

FIG. 33 illustrates a main PRBS used for all FFT modes according to anembodiment of the present invention.

FIG. 33(a) illustrates the main PRBS, and FIG. 33(b) illustrates aparameter Nmax for each FFT mode.

FIG. 34 illustrates a sub-PRBS used for FFT modes and an interleavingaddress for frequency interleaving according to an embodiment of thepresent invention.

FIG. 34(a) illustrates a sub-PRBS generator, and FIG. 34(b) illustratesan interleaving address for frequency interleaving. A cyclic shift valueaccording to an embodiment of the present invention may be referred toas a symbol offset.

FIG. 35 illustrates a write operation of a time interleaver according toan embodiment of the present invention.

FIG. 35 illustrates a write operation for two TI groups.

A left block in the figure illustrates a TI memory address array, andright blocks in the figure illustrate a write operation when two virtualFEC blocks and one virtual FEC block are inserted into heads of twocontiguous TI groups, respectively.

Hereinafter, description will be given of a configuration of a timeinterleaver and a time interleaving method using both a convolutionalinterleaver (CI) and a block interleaver (BI) or selectively usingeither the CI or the BI according to a physical layer pipe (PLP) mode. APLP according to an embodiment of the present invention is a physicalpath corresponding to the same concept as that of the above-describedDP, and a name of the PLP may be changed by a designer.

A PLP mode according to an embodiment of the present invention mayinclude a single PLP mode or a multi-PLP mode according to the number ofPLPs processed by a broadcast signal transmitter or a broadcast signaltransmission apparatus. The single PLP mode corresponds to a case inwhich one PLP is processed by the broadcast signal transmissionapparatus. The single PLP mode may be referred to as a single PLP.

The multi-PLP mode corresponds to a case in which one or more PLPs areprocessed by the broadcast signal transmission apparatus. The multi-PLPmode may be referred to as multiple PLPs.

In the present invention, time interleaving in which different timeinterleaving schemes are applied according to PLP modes may be referredto as hybrid time interleaving. Hybrid time interleaving according to anembodiment of the present invention is applied for each PLP (or at eachPLP level) in the multi-PLP mode.

FIG. 36 illustrates an interleaving type applied according to the numberof PLPs in a table.

In a time interleaving according to an embodiment of the presentinvention, an interleaving type may be determined based on a value ofPLP_NUM. PLP_NUM is a signaling field indicating a PLP mode. WhenPLP_NUM has a value of 1, the PLP mode corresponds to a single PLP. Thesingle PLP according to the present embodiment may be applied only to aCI.

When PLP_NUM has a value greater than 1, the PLP mode corresponds tomultiple PLPs. The multiple PLPs according to the present embodiment maybe applied to the CI and a BI. In this case, the CI may performinter-frame interleaving, and the BI may perform intra-frameinterleaving.

FIG. 37 is a block diagram including a first example of a structure of ahybrid time interleaver described above.

The hybrid time interleaver according to the first example may include aBI and a CI. The time interleaver of the present invention may bepositioned between a BICM chain block and a frame builder.

The BICM chain block illustrated in FIGS. 37 and 38 may include theblocks in the processing block 5000 of the BICM block illustrated inFIG. 19 except for the time interleaver 5050. The frame builderillustrated in FIGS. 37 and 38 may perform the same function as that ofthe frame building block 1020 of FIG. 18.

As described in the foregoing, it is possible to determine whether toapply the BI according to the first example of the structure of thehybrid time interleaver depending on values of PLP_NUM. That is, whenPLP_NUM=1, the BI is not applied (BI is turned OFF) and only the CI isapplied. When PLP_NUM>1, both the BI and the CI may be applied (BI isturned ON). A structure and an operation of the CI applied whenPLP_NUM>1 may be the same as or similar to a structure and an operationof the CI applied when PLP_NUM=1.

FIG. 38 is a block diagram including a second example of the structureof the hybrid time interleaver described above.

An operation of each block included in the second example of thestructure of the hybrid time interleaver is the same as the abovedescription in FIG. 20. It is possible to determine whether to apply aBI according to the second example of the structure of the hybrid timeinterleaver depending on values of PLP_NUM. Each block of the hybridtime interleaver according to the second example may perform operationsaccording to embodiments of the present invention. In this instance, anapplied structure and operation of a CI may be different between a caseof PLP_NUM=1 and a case of PLP_NUM>1.

FIG. 39 is a block diagram including a first example of a structure of ahybrid time deinterleaver.

The hybrid time deinterleaver according to the first example may performan operation corresponding to a reverse operation of the hybrid timeinterleaver according to the first example described above. Therefore,the hybrid time deinterleaver according to the first example of FIG. 39may include a convolutional deinterleaver (CDI) and a blockdeinterleaver (BDI).

A structure and an operation of the CDI applied when PLP_NUM>1 may bethe same as or similar to a structure and an operation of the CDIapplied when PLP_NUM=1.

It is possible to determine whether to apply the BDI according to thefirst example of the structure of the hybrid time deinterleaverdepending on values of PLP_NUM. That is, when PLP_NUM=1, the BDI is notapplied (BDI is turned OFF) and only the CDI is applied.

The CDI of the hybrid time deinterleaver may perform inter-framedeinterleaving, and the BDEI may perform intra-frame deinterleaving.Details of inter-frame deinterleaving and intra-frame deinterleaving arethe same as the above description.

A BICM decoding block illustrated in FIGS. 39 and 40 may perform areverse operation of the BICM chain block of FIGS. 37 and 38.

FIG. 40 is a block diagram including a second example of the structureof the hybrid time deinterleaver.

The hybrid time deinterleaver according to the second example mayperform an operation corresponding to a reverse operation of the hybridtime interleaver according to the second example described above. Anoperation of each block included in the second example of the structureof the hybrid time deinterleaver may be the same as the abovedescription in FIG. 39.

It is possible to determine whether to apply a BDI according to thesecond example of the structure of the hybrid time deinterleaverdepending on values of PLP_NUM. Each block of the hybrid timedeinterleaver according to the second example may perform operationsaccording to embodiments of the present invention. In this instance, anapplied structure and operation of a CDI may be different between a caseof PLP_NUM=1 and a case of PLP_NUM>1.

In the following specification, a method of transmitting/receivingcontent data and a signaling method in a broadcast system are described.Specifically, processing of a signal prior to the processing of aphysical layer signal is described in more detail.

In this specification, a fast information table (FIT) may also be calledlink layer signaling (LLS) or low level signaling (LLS). In thisspecification, all of the field/elements included in each table may notbe included and may be selectively included.

FIG. 41 is a view showing a protocol stack for a next generationbroadcasting system according to an embodiment of the present invention.

The broadcasting system according to the present invention maycorrespond to a hybrid broadcasting system in which an Internet Protocol(IP) centric broadcast network and a broadband are coupled.

The broadcasting system according to the present invention may bedesigned to maintain compatibility with a conventional MPEG-2 basedbroadcasting system.

The broadcasting system according to the present invention maycorrespond to a hybrid broadcasting system based on coupling of an IPcentric broadcast network, a broadband network, and/or a mobilecommunication network (or a cellular network).

Referring to the figure, a physical layer may use a physical protocoladopted in a broadcasting system, such as an ATSC system and/or a DVBsystem. For example, in the physical layer according to the presentinvention, a transmitter/receiver may transmit/receive a terrestrialbroadcast signal and convert a transport frame including broadcast datainto an appropriate form.

In an encapsulation layer, an IP datagram is acquired from informationacquired from the physical layer or the acquired IP datagram isconverted into a specific frame (for example, an RS Frame, GSE-lite,GSE, or a signal frame). The frame main include a set of IP datagrams.For example, in the encapsulation layer, the transmitter include dataprocessed from the physical layer in a transport frame or the receiverextracts an MPEG-2 TS and an IP datagram from the transport frameacquired from the physical layer.

A fast information channel (FIC) includes information (for example,mapping information between a service ID and a frame) necessary toaccess a service and/or content. The FIC may be named a fast accesschannel (FAC).

The broadcasting system according to the present invention may useprotocols, such as an Internet Protocol (IP), a User Datagram Protocol(UDP), a Transmission Control Protocol (TCP), an Asynchronous LayeredCoding/Layered Coding Transport (ALC/LCT), a Rate Control Protocol/RTPControl Protocol (RCP/RTCP), a Hypertext Transfer Protocol (HTTP), and aFile Delivery over Unidirectional Transport (FLUTE). A stack betweenthese protocols may refer to the structure shown in the figure.

In the broadcasting system according to the present invention, data maybe transported in the form of an ISO based media file format (ISOBMFF).An Electrical Service Guide (ESG), Non Real Time (NRT), Audio/Video(A/V), and/or general data may be transported in the form of theISOBMFF.

Transport of data through a broadcast network may include transport of alinear content and/or transport of a non-linear content.

Transport of RTP/RTCP based A/V and data (closed caption, emergencyalert message, etc.) may correspond to transport of a linear content.

An RTP payload may be transported in the form of an RTP/AV streamincluding a Network Abstraction Layer (NAL) and/or in a formencapsulated in an ISO based media file format. Transport of the RTPpayload may correspond to transport of a linear content. Transport inthe form encapsulated in the ISO based media file format may include anMPEG DASH media segment for NV, etc.

Transport of a FLUTE based ESG, transport of non-timed data, transportof an NRT content may correspond to transport of a non-linear content.These may be transported in an MIME type file form and/or a formencapsulated in an ISO based media file format. Transport in the formencapsulated in the ISO based media file format may include an MPEG DASHmedia segment for NV, etc.

Transport through a broadband network may be divided into transport of acontent and transport of signaling data.

Transport of the content includes transport of a linear content (NV anddata (closed caption, emergency alert message, etc.)), transport of anon-linear content (ESG, non-timed data, etc.), and transport of a MPEGDASH based Media segment (A/V and data).

Transport of the signaling data may be transport including a signalingtable (including an MPD of MPEG DASH) transported through a broadcastingnetwork.

In the broadcasting system according to the present invention,synchronization between linear/non-linear contents transported throughthe broadcasting network or synchronization between a contenttransported through the broadcasting network and a content transportedthrough the broadband may be supported. For example, in a case in whichone UD content is separately and simultaneously transported through thebroadcasting network and the broadband, the receiver may adjust thetimeline dependent upon a transport protocol and synchronize the contentthrough the broadcasting network and the content through the broadbandto reconfigure the contents as one UD content.

An applications layer of the broadcasting system according to thepresent invention may realize technical characteristics, such asInteractivity, Personalization, Second Screen, and automatic contentrecognition (ACR). These characteristics are important in extension fromATSC 2.0 to ATSC 3.0. For example, HTML5 may be used for acharacteristic of interactivity.

In a presentation layer of the broadcasting system according to thepresent invention, HTML and/or HTML5 may be used to identify spatial andtemporal relationships between components or interactive applications.

In the present invention, signaling includes signaling informationnecessary to support effective acquisition of a content and/or aservice. Signaling data may be expressed in a binary or XMK form. Thesignaling data may be transmitted through the terrestrial broadcastingnetwork or the broadband.

A real-time broadcast A/V content and/or data may be expressed in an ISOBase Media File Format, etc. In this case, the A/V content and/or datamay be transmitted through the terrestrial broadcasting network in realtime and may be transmitted based on IP/UDP/FLUTE in non-real time.Alternatively, the broadcast A/V content and/or data may be received byreceiving or requesting a content in a streaming mode using DynamicAdaptive Streaming over HTTP (DASH) through the Internet in real time.In the broadcasting system according to the embodiment of the presentinvention, the received broadcast A/V content and/or data may becombined to provide various enhanced services, such as an Interactiveservice and a second screen service, to a viewer.

In a hybrid-based broadcast system of a TS and an IP stream, a linklayer may be used to transmit data having a TS or IP stream type. Whenvarious types of data are to be transmitted through a physical layer,the link layer may convert the data into a format supported by thephysical layer and deliver the converted data to the physical layer. Inthis way, the various types of data may be transmitted through the samephysical layer. Here, the physical layer may correspond to a step oftransmitting data using an MIMO/MISO scheme or the like by interleaving,multiplexing, and/or modulating the data.

The link layer needs to be designed such that an influence on anoperation of the link layer is minimized even when a configuration ofthe physical layer is changed. In other words, the operation of the linklayer needs to be configured such that the operation may be compatiblewith various physical layers.

The present invention proposes a link layer capable of independentlyoperating irrespective of types of an upper layer and a lower layer. Inthis way, it is possible to support various upper layers and lowerlayers. Here, the upper layer may refer to a layer of a data stream suchas a TS stream, an IP stream, or the like. Here, the lower layer mayrefer to the physical layer. In addition, the present invention proposesa link layer having a correctable structure in which a functionsupportable by the link layer may be extended/added/deleted. Moreover,the present invention proposes a scheme of including an overheadreduction function in the link layer such that radio resources may beefficiently used.

In this figure, protocols and layers such as IP, UDP, TCP, ALC/LCT,RCP/RTCP, HTTP, FLUTE, and the like are as described above.

In this figure, a link layer t88010 may be another example of theabove-described data link (encapsulation) part. The present inventionproposes a configuration and/or an operation of the link layer t88010.The link layer t88010 proposed by the present invention may processsignaling necessary for operations of the link layer and/or the physicallayer. In addition, the link layer t88010 proposed by the presentinvention may encapsulate TS and IP packets and the like, and performoverhead reduction in this process.

The link layer t88010 proposed by the present invention may be referredto by several terms such as data link layer, encapsulation layer, layer2, and the like. According to a given embodiment, a new term may beapplied to the link layer and used.

FIG. 42 is a conceptual diagram illustrating an interface of a linklayer according to an embodiment of the present invention.

Referring to FIG. 42, the transmitter may consider an exemplary case inwhich IP packets and/or MPEG-2 TS packets mainly used in the digitalbroadcasting are used as input signals. The transmitter may also supporta packet structure of a new protocol capable of being used in the nextgeneration broadcast system. The encapsulated data of the link layer andsignaling information may be transmitted to a physical layer. Thetransmitter may process the transmitted data (including signaling data)according to the protocol of a physical layer supported by the broadcastsystem, such that the transmitter may transmit a signal including thecorresponding data.

On the other hand, the receiver may recover data and signalinginformation received from the physical layer into other data capable ofbeing processed in a upper layer. The receiver may read a header of thepacket, and may determine whether a packet received from the physicallayer indicates signaling information (or signaling data) or recognitiondata (or content data).

The signaling information (i.e., signaling data) received from the linklayer of the transmitter may include first signaling information that isreceived from an upper layer and needs to be transmitted to an upperlayer of the receiver; second signaling information that is generatedfrom the link layer and provides information regarding data processingin the link layer of the receiver; and/or third signaling informationthat is generated from the upper layer or the link layer and istransferred to quickly detect specific data (e.g., service, content,and/or signaling data) in a physical layer.

FIG. 43 illustrates an operation in a normal mode corresponding to oneof operation modes of a link layer according to an embodiment of thepresent invention.

The link layer proposed by the present invention may have variousoperation modes for compatibility between an upper layer and a lowerlayer. The present invention proposes a normal mode and a transparentmode of the link layer. Both the operation modes may coexist in the linklayer, and an operation mode to be used may be designated usingsignaling or a system parameter. According to a given embodiment, one ofthe two operation modes may be implemented. Different modes may beapplied according to an IP layer, a TS layer, and the like input to thelink layer. In addition, different modes may be applied for each streamof the IP layer and for each stream of the TS layer.

According to a given embodiment, a new operation mode may be added tothe link layer. The new operation mode may be added based onconfigurations of the upper layer and the lower layer. The new operationmode may include different interfaces based on the configurations of theupper layer and the lower layer. Whether to use the new operation modemay be designated using signaling or a system parameter.

In the normal mode, data may be processed through all functionssupported by the link layer, and then delivered to a physical layer.

First, each packet may be delivered to the link layer from an IP layer,an MPEG-2 TS layer, or another particular layer t89010. In other words,an IP packet may be delivered to the link layer from an IP layer.Similarly, an MPEG-2 TS packet may be delivered to the link layer fromthe MPEG-2 TS layer, and a particular packet may be delivered to thelink layer from a particular protocol layer.

Each of the delivered packets may go through or not go through anoverhead reduction process t89020, and then go through an encapsulationprocess t89030.

First, the IP packet may go through or not go through the overheadreduction process t89020, and then go through the encapsulation processt89030. Whether the overhead reduction process t89020 is performed maybe designated by signaling or a system parameter. According to a givenembodiment, the overhead reduction process t89020 may be performed ornot performed for each IP stream. An encapsulated IP packet may bedelivered to the physical layer.

Second, the MPEG-2 TS packet may go through the overhead reductionprocess t89020, and go through the encapsulation process t89030. TheMPEG-2 TS packet may not be subjected to the overhead reduction processt89020 according to a given embodiment. However, in general, a TS packethas sync bytes (0x47) and the like at the front and thus it may beefficient to eliminate such fixed overhead. The encapsulated TS packetmay be delivered to the physical layer.

Third, a packet other than the IP or TS packet may or may not go throughthe overhead reduction process t89020, and then go through theencapsulation process t89030. Whether or not the overhead reductionprocess t89020 is performed may be determined according tocharacteristics of the corresponding packet. Whether the overheadreduction process t89020 is performed may be designated by signaling ora system parameter. The encapsulated packet may be delivered to thephysical layer.

In the overhead reduction process t89020, a size of an input packet maybe reduced through an appropriate scheme. In the overhead reductionprocess t89020, particular information may be extracted from the inputpacket or generated. The particular information is information relatedto signaling, and may be transmitted through a signaling region. Thesignaling information enables a receiver to restore an original packetby restoring changes due to the overhead reduction process t89020. Thesignaling information may be delivered to a link layer signaling processt89050.

The link layer signaling process t89050 may transmit and manage thesignaling information extracted/generated in the overhead reductionprocess t89020. The physical layer may have physically/logically dividedtransmission paths for signaling, and the link layer signaling processt89050 may deliver the signaling information to the physical layeraccording to the divided transmission paths. Here, the above-describedFIC signaling process t89060, EAS signaling process t89070, or the likemay be included in the divided transmission paths. Signaling informationnot transmitted through the divided transmission paths may be deliveredto the physical layer through the encapsulation process t89030.

Signaling information managed by the link layer signaling process t89050may include signaling information delivered from the upper layer,signaling information generated in the link layer, a system parameter,and the like. Specifically, the signaling information may includesignaling information delivered from the upper layer to be subsequentlydelivered to an upper layer of the receiver, signaling informationgenerated in the link layer to be used for an operation of a link layerof the receiver, signaling information generated in the upper layer orthe link layer to be used for rapid detection in a physical layer of thereceiver, and the like.

Data going through the encapsulation process t89030 and delivered to thephysical layer may be transmitted through a data pipe (DP) t89040. Here,the DP may be a physical layer pipe (PLP). Signaling informationdelivered through the above-described divided transmission paths may bedelivered through respective transmission paths. For example, an FICsignal may be transmitted through an FIC t89080 designated in a physicalframe. In addition, an EAS signal may be transmitted through an EACt89090 designated in a physical frame. Information about presence of adedicated channel such as the FIC, the EAC, or the like may betransmitted to a preamble area of the physical layer through signaling,or signaled by scrambling a preamble using a particular scramblingsequence. According to a given embodiment, FIC signaling/EAS signalinginformation may be transmitted through a general DP area, PLS area, orpreamble rather than a designated dedicated channel.

The receiver may receive data and signaling information through thephysical layer. The receiver may restore the received data and signalinginformation into a form processable in the upper layer, and deliver therestored data and signaling information to the upper layer. This processmay be performed in the link layer of the receiver. The receiver mayverify whether a received packet is related to the signaling informationor the data by reading a header of the packet and the like. In addition,when overhead reduction is performed at a transmitter, the receiver mayrestore a packet, overhead of which has been reduced through theoverhead reduction process, to an original packet. In this process, thereceived signaling information may be used.

FIG. 44 illustrates an operation in a transparent mode corresponding toone of operation modes of a link layer according to an embodiment of thepresent invention.

In the transparent mode, data may not be subjected to functionssupported by the link layer or may be subjected to some of thefunctions, and then delivered to a physical layer. In other words, inthe transparent mode, a packet delivered to an upper layer may bedelivered to a physical layer without going through a separate overheadreduction and/or encapsulation process. Other packets may go through theoverhead reduction and/or encapsulation process as necessary. Thetransparent mode may be referred to as a bypass mode, and another termmay be applied to the transparent mode.

According to a given embodiment, some packets may be processed in thenormal mode and some packets may be processed in the transparent modebased on characteristics of the packets and a system operation.

A packet to which the transparent mode may be applied may be a packethaving a type well known to a system. When the packet may be processedin the physical layer, the transparent mode may be used. For example, awell-known TS or IP packet may go through separate overhead reductionand input formatting processes in the physical layer and thus thetransparent mode may be used in a link layer step. When the transparentmode is applied and a packet is processed through input formatting andthe like in the physical layer, an operation such as the above-describedTS header compression may be performed in the physical layer. On theother hand, when the normal mode is applied, a processed link layerpacket may be treated as a GS packet and processed in the physicallayer.

In the transparent mode, a link layer signaling module may be includedwhen signal transmission needs to be supported. As described above, thelink layer signaling module may transmit and manage signalinginformation. The signaling information may be encapsulated andtransmitted through a DP, and FIC signaling information and EASsignaling information having divided transmission paths may betransmitted through an FIC and an EAC, respectively.

In the transparent mode, whether information corresponds to signalinginformation may be displayed using a fixed IP address and port number.In this case, the signaling information may be filtered to configure alink layer packet, and then transmitted through the physical layer.

FIG. 45 illustrates a configuration of a link layer at a transmitteraccording to an embodiment of the present invention (normal mode).

The present embodiment is an embodiment presuming that an IP packet isprocessed. The link layer at the transmitter may largely include a linklayer signaling part for processing signaling information, an overheadreduction part, and/or an encapsulation part from a functionalperspective. The link layer at the transmitter may further include ascheduler t91020 for a control of the entire operation of the link layerand scheduling, input and output parts of the link layer, and/or thelike.

First, upper layer signaling information and/or system parameter t91010may be delivered to the link layer. In addition, an IP stream includingIP packets may be delivered to the link layer from an IP layer t91110.

As described above, the scheduler t91020 may determine and controloperations of several modules included in the link layer. The deliveredsignaling information and/or system parameter t91010 may be filtered orused by the scheduler t91020. Information corresponding to a part of thedelivered signaling information and/or system parameter t91010 andnecessary for a receiver may be delivered to the link layer signalingpart. In addition, information corresponding to a part of the signalinginformation and necessary for an operation of the link layer may bedelivered to an overhead reduction control block t91120 or anencapsulation control block t91180.

The link layer signaling part may collect information to be transmittedas signaling in the physical layer, and transform/configure theinformation in a form suitable for transmission. The link layersignaling part may include a signaling manager t91030, a signalingformatter t91040, and/or a buffer for channels t91050.

The signaling manager t91030 may receive signaling information deliveredfrom the scheduler t91020, signaling delivered from the overheadreduction part, and/or context information. The signaling manager t91030may determine paths for transmission of the signaling information withrespect to delivered data. The signaling information may be deliveredthrough the paths determined by the signaling manager t91030. Asdescribed in the foregoing, signaling information to be transmittedthrough divided channels such as an FIC, an EAS, and the like may bedelivered to the signaling formatter t91040, and other signalinginformation may be delivered to an encapsulation buffer t91070.

The signaling formatter t91040 may format associated signalinginformation in forms suitable for respective divided channels so thatthe signaling information may be transmitted through separately dividedchannels. As described in the foregoing, the physical layer may includephysically/logically divided separate channels. The divided channels maybe used to transmit FIC signaling information or EAS-relatedinformation. The FIC or EAS-related information may be divided by thesignaling manager t91030 and input to the signaling formatter t91040.The signaling formatter t91040 may format information such that theinformation is suitable for respective separate channels. Besides theFIC and the EAS, when the physical layer is designed to transmitparticular signaling information through separately divided channels, asignaling formatter for the particular signaling information may beadded. Through this scheme, the link layer may be compatible withvarious physical layers.

The buffer for channels t91050 may deliver signaling informationdelivered from the signaling formatter t91040 to designated dedicatedchannels t91060. The number and content of the dedicated channels t91060may vary depending on an embodiment.

As described in the foregoing, the signaling manager t91030 may deliversignaling information which is not delivered to a dedicated channel tothe encapsulation buffer t91070. The encapsulation buffer t91070 mayfunction as a buffer that receives the signaling information notdelivered to the dedicated channel.

An encapsulation for signaling information t91080 may encapsulate thesignaling information not delivered to the dedicated channel. Atransmission buffer t91090 may function as a buffer that delivers theencapsulated signaling information to a DP for signaling informationt91100. Here, the DP for signaling information t91100 may refer to theabove-described PLS area.

The overhead reduction part may allow efficient transmission byeliminating overhead of packets delivered to the link layer. It ispossible to configure overhead reduction parts, the number of which isthe same as the number of IP streams input to the link layer.

An overhead reduction buffer t91130 may receive an IP packet deliveredfrom an upper layer. The delivered IP packet may be input to theoverhead reduction part through the overhead reduction buffer t91130.

An overhead reduction control block t91120 may determine whether toperform overhead reduction on a packet stream input to the overheadreduction buffer t91130. The overhead reduction control block t91120 maydetermine whether to perform overhead reduction for each packet stream.When overhead reduction is performed on the packet stream, packets maybe delivered to an RoHC compressor t91140 and overhead reduction may beperformed. When overhead reduction is not performed on the packetstream, packets may be delivered to the encapsulation part andencapsulation may be performed without overhead reduction. Whether toperform overhead reduction on packets may be determined by signalinginformation t91010 delivered to the link layer. The signalinginformation t91010 may be delivered to the encapsulation control blockt91180 by the scheduler t91020.

The RoHC compressor t91140 may perform overhead reduction on a packetstream. The RoHC compressor t91140 may compress headers of packets.Various schemes may be used for overhead reduction. Overhead reductionmay be performed by schemes proposed in the present invention. Thepresent embodiment presumes an IP stream and thus the compressor isexpressed as the RoHC compressor. However, the term may be changedaccording to a given embodiment. In addition, an operation is notrestricted to compression of an IP stream, and overhead reduction may beperformed on all types of packets by the RoHC compressor t91140.

A packet stream configuration block t91150 may divide IP packets havingcompressed headers into information to be transmitted to a signalingregion and information to be transmitted to a packet stream. Theinformation to be transmitted to the packet stream may refer toinformation to be transmitted to a DP area. The information to betransmitted to the signaling region may be delivered to a signalingand/or context control block t91160. The information to be transmittedto the packet stream may be transmitted to the encapsulation part.

The signaling and/or context control block t91160 may collect signalingand/or context information and deliver the collected information to thesignaling manager t91030. In this way, the signaling and/or contextinformation may be transmitted to the signaling region.

The encapsulation part may encapsulate packets in suitable forms suchthat the packets may be delivered to the physical layer. The number ofconfigured encapsulation parts may be the same as the number of IPstreams.

An encapsulation buffer t91170 may receive a packet stream forencapsulation. Packets subjected to overhead reduction may be receivedwhen overhead reduction is performed, and an input IP packet may bereceived without change when overhead reduction is not performed.

An encapsulation control block t91180 may determine whether to performencapsulation on an input packet stream. When encapsulation isperformed, the packet stream may be delivered tosegmentation/concatenation t91190. When encapsulation is not performed,the packet stream may be delivered to a transmission buffer t91230.Whether to perform encapsulation of packets may be determined based onthe signaling information t91010 delivered to the link layer. Thesignaling information t91010 may be delivered to the encapsulationcontrol block t91180 by the scheduler t91020.

In the segmentation/concatenation t91190, the above-descriedsegmentation or concatenation operation may be performed on packets. Inother words, when an input IP packet is longer than a link layer packetcorresponding to an output of the link layer, one IP packet may bedivided into several segments to configure a plurality of link layerpacket payloads. In addition, when the input IP packet is shorter thanthe link layer packet corresponding to the output of the link layer,several IP packets may be combined to configure one link layer packetpayload.

A packet configuration table t91200 may have information about aconfiguration of segmented and/or concatenated link layer packets. Atransmitter and a receiver may have the same information of the packetconfiguration table t91200. The transmitter and the receiver may referto the information of the packet configuration table t91200. An indexvalue of the information of the packet configuration table t91200 may beincluded in headers of the link layer packets.

A link layer header information block t91210 may collect headerinformation generated in an encapsulation process. In addition, the linklayer header information block t91210 may collect information includedin the packet configuration table t91200. The link layer headerinformation block t91210 may configure header information according to aheader configuration of a link layer packet.

A header attachment block t91220 may add headers to payloads of thesegmented and/or concatenated link layer packets. The transmissionbuffer t91230 may function as a buffer for delivering a link layerpacket to a DP t91240 of the physical layer.

Each block or module and parts may be configured as one module/protocolor a plurality of modules/protocols in the link layer.

FIG. 46 illustrates a configuration of a link layer at a receiveraccording to an embodiment of the present invention (normal mode).

The present embodiment is an embodiment presuming that an IP packet isprocessed. The link layer at the receiver may largely include a linklayer signaling part for processing signaling information, an overheadprocessing part, and/or a decapsulation part from a functionalperspective. The link layer at the receiver may further include ascheduler for a control of the entire operation of the link layer andscheduling, input and output parts of the link layer, and/or the like.

First, information received through a physical layer may be delivered tothe link layer. The link layer may process the information to restorethe information to an original state in which the information is not yetprocessed by a transmitter, and deliver the information to an upperlayer. In the present embodiment, the upper layer may be an IP layer.

Information delivered through dedicated channels t92030 separated fromthe physical layer may be delivered to the link layer signaling part.The link layer signaling part may distinguish signaling informationreceived from the physical layer, and deliver the distinguishedsignaling information to each part of the link layer.

A buffer for channels t92040 may function as a buffer that receivessignaling information transmitted through the dedicated channels. Asdescribed above, when physically/logically divided separate channels arepresent in the physical layer, it is possible to receive signalinginformation transmitted through the channels. When the informationreceived from the separate channels is in a divided state, the dividedinformation may be stored until the information is in a complete form.

A signaling decoder/parser t92050 may check a format of signalinginformation received through a dedicated channel, and extractinformation to be used in the link layer. When the signaling informationreceived through the dedicated channel is encoded, decoding may beperformed. In addition, according to a given embodiment, it is possibleto check integrity of the signaling information.

A signaling manager t92060 may integrate signaling information receivedthrough several paths. Signaling information received through a DP forsignaling t92070 to be described below may be integrated by thesignaling manager t92060. The signaling manager t92060 may deliversignaling information necessary for each part in the link layer. Forexample, context information for recovery of a packet and the like maybe delivered to the overhead processing part. In addition, signalinginformation for control may be delivered to a scheduler t92020.

General signaling information not received through a separate dedicatedchannel may be received through the DP for signaling t92070. Here, theDP for signaling may refer to a PLS or the like. A reception buffert92080 may function as a buffer for receiving the signaling informationreceived from the DP for signaling t92070. The received signalinginformation may be decapsulated in a decapsulation for signalinginformation block t92090. The decapsulated signaling information may bedelivered to the signaling manager t92060 through a decapsulation buffert92100. As described in the foregoing, the signaling manager t92060 maycollect signaling information and deliver the collected signalinginformation to a desired part in the link layer.

The scheduler t92020 may determine and control operations of severalmodules included in the link layer. The scheduler t92020 may controleach part of the link layer using receiver information t92010 and/orinformation delivered from the signaling manager t92060. In addition,the scheduler t92020 may determine an operation mode and the like ofeach part. Here, the receiver information t92010 may refer toinformation previously stored by the receiver. The scheduler t92020 mayuse information changed by a user such as a channel change and the likefor control.

The decapsulation part may filter a packet received from a DP t92110 ofthe physical layer, and separate the packet based on a type of thepacket. The number of configured decapsulation parts may be the same asthe number of DPs that may be simultaneously decoded in the physicallayer.

A decapsulation buffer t92120 may function as a buffer that receives apacket stream from the physical layer to perform decapsulation. Adecapsulation control block t92130 may determine whether to decapsulatethe received packet stream. When decapsulation is performed, the packetstream may be delivered to a link layer header parser t92140. Whendecapsulation is not performed, the packet stream may be delivered to anoutput buffer t92220. The signaling information delivered from thescheduler t92020 may be used to determine whether to performdecapsulation.

The link layer header parser t92140 may identify a header of a receivedlink layer packet. When the header is identified, it is possible toidentify a configuration of an IP packet included in a payload of thelink layer packet. For example, the IP packet may be segmented orconcatenated.

A packet configuration table t92150 may include payload information oflink layer packets configured through segmentation and/or concatenation.The transmitter and the receiver may have the same information asinformation of the packet configuration table t92150. The transmitterand the receiver may refer to the information of the packetconfiguration table t92150. A value necessary for reassembly may befound based on index information included in the link layer packets.

A reassembly block t92160 may configure payloads of the link layerpackets configured through segmentation and/or concatenation as packetsof an original IP stream. The reassembly block t92160 may reconfigureone IP packet by collecting segments, or reconfigure a plurality of IPpacket streams by separating concatenated packets. The reassembled IPpackets may be delivered to the overhead processing part.

The overhead processing part may perform a reverse process of overheadreduction performed by the transmitter. In the reverse process, anoperation of returning packets experiencing overhead reduction tooriginal packets is performed. This operation may be referred to asoverhead processing. The number of configured overhead processing partsmay be the same as the number of DPs that may be simultaneously decodedin the physical layer.

A packet recovery buffer t92170 may function as a buffer that receivesan RoHC packet or an IP packet decapsulated for overhead processing.

An overhead control block t92180 may determine whether to perform packetrecovery and/or decompression of decapsulated packets. When the packetrecovery and/or decompression are performed, the packets may bedelivered to a packet stream recovery t92190. When the packet recoveryand/or decompression are not performed, the packets may be delivered tothe output buffer t92220. Whether to perform the packet recovery and/ordecompression may be determined based on the signaling informationdelivered by the scheduler t92020.

The packet stream recovery t92190 may perform an operation ofintegrating a packet stream separated from the transmitter and contextinformation of the packet stream. The operation may correspond to aprocess of restoring the packet stream such that the packet stream maybe processed by an RoHC decompressor t92210. In this process, signalinginformation and/or context information may be delivered from a signalingand/or context control block t92200. The signaling and/or contextcontrol block t92200 may distinguish signaling information deliveredfrom the transmitter and deliver the signaling information to the packetstream recovery t92190 such that the signaling information may be mappedto a stream suitable for a context ID.

The RoHC decompressor t92210 may recover headers of packets of a packetstream. When the headers are recovered, the packets of the packet streammay be restored to original IP packets. In other words, the RoHCdecompressor t92210 may perform overhead processing.

The output buffer t92220 may function as a buffer before delivering anoutput stream to an IP layer t92230.

The link layer of the transmitter and the receiver proposed in thepresent invention may include the blocks or modules described above. Inthis way, the link layer may independently operate irrespective of theupper layer and the lower layer, and efficiently perform overheadreduction. In addition, a function which is supportable depending on theupper and lower layers may be easily extended/added/deleted.

FIG. 47 is a diagram illustrating definition according to link layerorganization type according to an embodiment of the present invention.

When a link layer is actually embodied as a protocol layer, a broadcastservice can be transmitted and received through one frequency slot.Here, an example of one frequency slot may be a broadcast channel thatmainly has a specific bandwidth. As described above, according to thepresent invention, in a broadcast system in which a configuration of aphysical layer is changed or in a plurality of broadcast systems withdifferent physical layer configurations, a compatible link layer may bedefined.

The physical layer may have a logical data path for an interface of alink layer. The link layer may access the logical data path of thephysical layer and transmit information associated with thecorresponding data path to the logical data path. The following typesmay be considered as the data path of the physical layer interfaced withthe link layer.

In a broadcast system, a normal data pipe (Normal DP) may exist as atype of data path. The normal data pipe may be a data pipe fortransmission of normal data and may include one or more data pipesaccording to a configuration of a physical layer.

In a broadcast system, a base data pipe (Base DP) may exist as a type ofdata path. The base data pipe may be a data pipe used for specificpurpose and may transmit signaling information (entire or partialsignaling information described in the present invention) and/or commondata in a corresponding frequency slot. As necessary, in order toeffectively manage a bandwidth, data that is generally transmittedthrough a normal data pipe may be transmitted through a base data pipe.When the amount of information to be transmitted when a dedicatedchannel is present exceeds processing capacity of a correspondingchannel, the base data pipe may perform a complementary function. Thatis, data that exceeds the processing capacity of the correspondingchannel may be transmitted through the base data pipe.

In general, the base data pipe continuously uses one designated datapipe. However, one or more data pipes may be dynamically selected forthe base data pipe among a plurality of data pipes using a method suchas physical layer signaling, link layer signaling, or the like in orderto effectively manage a data pipe.

In a broadcast system, a dedicated channel may exist as a type of datapath. The dedicated channel may be a channel used for signaling in aphysical layer or a similar specific purpose and may include a fastinformation channel (FIC) for rapidly acquiring matters that are mainlyserved on a current frequency slot and/or an emergency alert channel(EAC) for immediately transmitting notification of emergency alert to auser.

In general, a logical data path is embodied in a physical layer in orderto transmit the normal data pipe. A logical data path for the base datapipe and/or the dedicated channel may not be embodied in a physicallayer.

A configuration of data to be transmitted in the link layer may bedefined as illustrated in the drawing.

Organization Type 1 may refer to the case in which a logical data pathincludes only a normal data pipe.

Organization Type 2 may refer to the case in which a logical data pathincludes a normal data pipe and a base data pipe.

Organization Type 3 may refer to the case in which a logical data pathincludes a normal data pipe and a dedicated channel.

Organization Type 4 may refer to the case in which a logical data pathincludes a normal data pipe, a data base pipe, and a dedicated channel.

As necessary, the logical data path may include a base data pipe and/ora dedicated channel.

According to an embodiment of the present invention, a transmissionprocedure of signaling information may be determined according toconfiguration of a logical data path. Detailed information of signalingtransmitted through a specific logical data path may be determinedaccording to a protocol of a upper layer of a link layer defined in thepresent invention. Regarding a procedure described in the presentinvention, signaling information parsed through a upper layer may alsobe used and corresponding signaling may be transmitted in the form of anIP packet from the upper layer and transmitted again after beingencapsulated in the form of a link layer packet.

When such signaling information is transmitted, a receiver may extractdetailed signaling information from session information included in anIP packet stream according to protocol configuration. When signalinginformation of a upper layer is used, a database (DB) may be used or ashared memory may be used. For example, in the case of extracting thesignaling information from the session information included in the IPpacket stream, the extracted signaling information may be stored in aDB, a buffer, and/or a shared memory of the receiver. Next, when thesignaling information is needed in a procedure of processing data in abroadcast signal, the signaling information may be obtained from theabove storage device.

FIG. 48 is a diagram illustrating processing of a broadcast signal whena logical data path includes only a normal data pipe according to anembodiment of the present invention.

The diagram illustrates a structure of a link layer when the logical ofthe physical layer includes only a normal data pipe. As described above,the link layer may include a link layer signaling processor, an overheadreduction processor, and an encapsulation (decapsulation) processor.Transmission of information output from each functional module (whichmay be embodied as hardware or software) to an appropriate data path ofthe physical layer may be one of main functions of the link layer.

With regard to an IP stream configured on a upper layer of a link layer,a plurality of packet streams may be transmitted according to a datarate at which data is to be transmitted, and overhead reduction andencapsulation procedures may be performed for each respectivecorresponding packet stream. A physical layer may include a data pipe(DP) as a plurality of logical data paths that a link layer can accessin one frequency band and may transmit a packet stream processed in alink layer for each respective packet stream. When the number of DPs islower than that of packet streams to be transmitted, some of the packetstreams may be multiplexed and input to a DP in consideration of a datarate.

The signaling processor may check transmission system information,related parameters, and/or signaling transmitted in a upper layer andcollect information to be transmitted via signaling. Since only a normaldata pipe is configured in a physical layer, corresponding signalingneeds to be transmitted in the form of packet. Accordingly, signalingmay be indicated using a header, etc. of a packet during link layerpacket configuration. In this case, a header of a packet includingsignaling may include information for identifying whether signaling datais contained in a payload of the packet.

In the case of service signaling transmitted in the form of IP packet ina upper layer, in general, it is possible to process different IPpackets in the same way. However, information of the corresponding IPpacket can be read for a configuration of link layer signaling. To thisend, a packet including signaling may be found using a filtering methodof an IP address. For example, since IANA designates an IP address of224.0.23.60 as ATSC service signaling, the receiver may check an IPpacket having the corresponding IP address use the IP packet forconfiguration of link layer signaling. In this case, the correspondingpacket needs to also be transmitted to a receiver, processing for the IPpacket is performed without change. The receiver may parse an IP packettransmitted to a predetermined IP address and acquire data for signalingin a link layer.

When a plurality of broadcast services are transmitted through onefrequency band, the receiver does not have to decode all DPs, and it isefficient to pre-check signaling information and to decode only a DPassociated with a required service. Accordingly, with regard to anoperation for a link layer of the receiver, the following procedures maybe performed.

When a user selects or changes a service to be received, the receivertunes a corresponding frequency and reads information of the receiver,stored in a DB, etc. with regard to a corresponding channel.

The receiver checks information about a DP that transmits link layersignaling and decodes the corresponding DP to acquire a link layersignaling packet.

The receiver parses the link layer signaling packet and acquiresinformation about a DP that transmits data associated with a serviceselected by the user among one or more DPs transmitted through a currentchannel and overhead reduction information about a packet stream of thecorresponding DP. The receiver may acquire information foridentification of a DP that transmits the data associated with theservice selected by the user from a link layer signaling packet andobtain a corresponding DP based on the information. In addition, thelink layer signaling packet may include information indicating overheadreduction applied to the corresponding DP, and the receiver may restorea DP to which overhead reduction is applied, using the information.

The receiver transmits DP information to be received, to a physicallayer processor that processes a signal or data in a physical layer andreceives a packet stream from a corresponding DP.

The receiver performs encapsulation and header recovery on the packetstream decoded by the physical layer processor.

Then the receiver performs processing according to a protocol of a upperlayer and provides a broadcast service to the user.

FIG. 49 is a diagram illustrating processing of a broadcast signal whena logical data path includes a normal data pipe and a base data pipeaccording to an embodiment of the present invention.

The diagram illustrates a structure of a link layer when the logicaldata path of the physical layer includes a base data pipe and a normaldata pipe. As described above, the link layer may include a link layersignaling part, an overhead reduction part, and an encapsulation(decapsulation) part. In this case, a link layer processor forprocessing a signal and/or data in a link layer may include a link layersignaling processor, an overhead reduction processor, and anencapsulation (decapsulation) processor.

Transmission of information output from each functional module (whichmay be embodied as hardware or software) to an appropriate data path ofthe physical layer may be one of main functions of the link layer.

With regard to an IP stream configured on a upper layer of a link layer,a plurality of packet streams may be transmitted according to a datarate at which data is to be transmitted, and overhead reduction andencapsulation procedures may be performed for each respectivecorresponding packet stream.

A physical layer may include a data pipe (DP) as a plurality of logicaldata paths that a link layer can access in one frequency band and maytransmit a packet stream processed in a link layer for each respectivepacket stream. When the number of DPs is lower than that of packetstreams to be transmitted, some of the packet streams may be multiplexedand input to a DP in consideration of a data rate.

The signaling processor may check transmission system information,related parameters, upper layer signaling, etc. and collect informationto be transmitted via signaling. Since a broadcast signal of thephysical layer includes a base DP and a normal DP, signaling may betransmitted to the base DP and signaling data may be transmitted in theform of packet appropriate for transmission of the base DP inconsideration of a data rate. In this case, signaling may be indicatedusing a header, etc. of a packet during link layer packet configuration.For example, a header of a link layer packet may include informationindicating that data contained in a payload of the packet is signalingdata.

In a physical layer structure in which a logical data path such as abase DP exists, it may be efficient to transmit data that is notaudio/video content, such as signaling information to the base DP inconsideration of a data rate. Accordingly, service signaling that istransmitted in the form of IP packet in a upper layer may be transmittedto the base DP using a method such as IP address filtering, etc. Forexample, IANA designates an IP address of 224.0.23.60 as ATSC servicesignaling, an IP packet stream with the corresponding IP address may betransmitted to the base DP.

When a plurality of IP packet streams about corresponding servicesignaling is present, the IP packet streams may be transmitted to onebase DP using a method such as multiplexing, etc. However, a packetabout different service signaling may be divided into field values suchas a source address and/or a port. In this case, information requiredfor configuration of link layer signaling can also be read from thecorresponding service signaling packet.

When a plurality of broadcast services are transmitted through onefrequency band, the receiver may not have to decode all DPs, maypre-check signaling information, and may decode only a DP that transmitsdata and/or a signal about a corresponding service. Accordingly, thereceiver may perform the following operation with regard to data and/orprocessing in a link layer.

When a user selects or changes a service to be received, the receivertunes a corresponding frequency and reads information of the receiver,stored in a DB, etc. with regard to a corresponding channel. Here, theinformation stored in the DB, etc. may include information foridentification of the base DP.

The receiver decodes the base DP and acquires a link layer signalingpacket included in the base DP.

The receiver parses the link layer signaling packet to acquire DPinformation for reception of the service selected by the user andoverhead reduction information about a packet stream of thecorresponding DP among a plurality of DPs transmitted through a currentchannel and overhead reduction information about a packet stream of thecorresponding DP. The link layer signaling packet may includeinformation for identification of a DP that transmits a signal and/ordata associated with a specific service, and/or information foridentification of a type of overhead reduction applied to a packetstream transmitted to the corresponding DP. The receiver may access oneor more DPs or restore the packet included in the corresponding DP usingthe above information.

The receiver is a physical layer processor that processes a signaland/or data according to a protocol of a physical layer, transmitsinformation about a DP to be received for a corresponding service, andreceives a packet stream from the corresponding DP.

The receiver performs decapsulation and header recovery on the packetstream decoded in the physical layer and transmits the packet stream toa upper layer of the receiver in the form of IP packet stream.

Then, the receiver performs processing according to a upper layerprotocol and provides a broadcast service to the user.

In the above-described process of acquiring the link layer packet bydecoding the base DP, information about the base DP (e.g., an identifier(ID) information of the base DP, location information of the base DP, orsignaling information included in the base DP) may be acquired duringprevious channel scan and then stored in a DB and the receiver may usethe stored base DP. Alternatively, the receiver may acquire the base DPby first seeking a DP that the receiver has pre-accessed.

In the above-described process of acquiring the DP information for aservice selected by the user and the overhead reduction informationabout a DP packet stream transmitting the corresponding service, byparsing the link layer packet, if the information about the DPtransmitting the service selected by the user is transmitted throughupper layer signaling (e.g., a layer higher than a link layer, or an IPlayer), the receiver may acquire corresponding information from the DB,the buffer, and/or the shared memory as described above and use theacquired information as information about a DP requiring decoding.

If link layer signaling (link layer signaling information) and normaldata (e.g., broadcast content data) is transmitted through the same DPor if only a DP of one type is used in a broadcast system, the normaldata transmitted through the DP may be temporarily stored in the bufferor the memory while the signaling information is decoded and parsed.Upon acquiring the signaling information, the receiver may transmit acommand for extracting a DP that should be obtained according to thecorresponding signaling information to a device for extracting andprocessing the DP by a method using interior command words of thesystem.

FIG. 50 is a diagram illustrating processing of a broadcast signal whena logical data path includes a normal data pipe and a dedicated channelaccording to an embodiment of the present invention.

The diagram illustrates a structure of a link layer when the logicaldata path of the physical layer includes a dedicated channel and anormal data pipe. As described above, the link layer may include a linklayer signaling part, an overhead reduction part, and an encapsulation(decapsulation) part. In this regard, a link layer processor to beincluded in the receiver may include a link layer signaling processor,an overhead reduction processor, and/or an encapsulation (decapsulation)processor. Transmission of information output from each functionalmodule (which may be embodied as hardware or software) to an appropriatedata path of the physical layer may be one of main functions of the linklayer.

With regard to an IP stream configured on a upper layer of a link layer,a plurality of packet streams may be transmitted according to a datarate at which data is to be transmitted, and overhead reduction andencapsulation procedures may be performed for each respectivecorresponding packet stream. A physical layer may include a data pipe(DP) as a plurality of logical data paths that a link layer can accessin one frequency band and may transmit a packet stream processed in alink layer for each respective packet stream. When the number of DPs islower than that of packet streams to be transmitted, some of the packetstreams may be multiplexed and input to a DP in consideration of a datarate.

The signaling processor may check transmission system information,related parameters, upper layer signaling, etc. and collect informationto be transmitted via signaling. In a physical layer structure in whicha logical data path such as a dedicate channel exists, it may beefficient to mainly transmit signaling information through a dedicatedchannel in consideration of a data rate. However, when a large amount ofdata needs to be transmitted through a dedicated channel, a bandwidthfor the dedicated channel corresponding to the amount of the dedicatedchannel needs to be occupied, and thus it is general to set a high datarate of the dedicated channel. In addition, since a dedicated channel isgenerally received and decoded at higher speed than a DP, it is moreefficient to signaling data in terms of information that needs to berapidly acquired from the receiver. As necessary, when sufficientsignaling data cannot be transmitted through the dedicated channel,signaling data such as the aforementioned link layer signaling packetmay be transmitted through the normal DP, and signaling data transmittedthrough the dedicated channel may include information for identificationof the corresponding link layer signaling packet.

A plurality of dedicated channels may exist as necessary and a channelmay be enable/disable according to a physical layer.

In the case of service signaling transmitted in the form of IP packet ina upper layer, in general, it is possible to process different IPpackets in the same way. However, information of the corresponding IPpacket can be read for a configuration of link layer signaling. To thisend, a packet including signaling may be found using a filtering methodof an IP address. For example, since IANA designates an IP address of224.0.23.60 as ATSC service signaling, the receiver may check an IPpacket having the corresponding IP address use the IP packet forconfiguration of link layer signaling. In this case, the correspondingpacket needs to also be transmitted to a receiver, processing for the IPpacket is performed without change.

When a plurality of IP packet streams about service signaling ispresent, the IP packet streams may be transmitted to one DP togetherwith audio/video data using a method such as multiplexing, etc. However,a packet about service signaling and audio/video data may be dividedinto field values of an IP address, a port, etc.

When a plurality of broadcast services are transmitted through onefrequency band, the receiver does not have to decode all DPs, and it isefficient to pre-check signaling information and to decode only a DPthat transmit signal and/or data associated with a required service.Thus, the receiver may perform processing according to a protocol of alink layer as the following procedure.

When a user selects or changes a service to be received, the receivertunes a corresponding frequency and reads information stored in a DB,etc. with regard to a corresponding channel. The information stored inthe DB may include information for identification of a dedicated channeland/or signaling information for acquisition of channel/service/program.

The receiver decodes data transmitted through the dedicated channel andperforms processing associated with signaling appropriate for purpose ofthe corresponding channel. For example, a dedicated channel fortransmission of FIC may store and update information such as a serviceand/or a channel, and a dedicated channel for transmission of EAC maytransmit emergency alert information.

The receiver may acquire information of DP to be decoded usinginformation transmitted to the dedicated channel. As necessary, whenlink layer signaling is transmitted through a DP, the receiver maypre-decode a DP that transmits signaling and transmit the DP to adedicated channel in order to pre-acquire signaling information. Inaddition, a packet for link layer signaling may be transmitted through anormal DP, and in this case, the signaling data transmitted through thededicated channel may include information for identification of a DPincluding a packet for link layer signaling.

The receiver acquires DP information for reception of a service selectedby a user among a plurality of DPs that are transmitted to a currentchannel and overhead reduction information about a packet stream of thecorresponding DP using the link layer signaling information. The linklayer signaling information may include information for identificationof a DP for transmission of a signal and/or data associated with aspecific service, and/or information for identification of a type ofoverhead reduction applied to a packet stream transmitted to thecorresponding DP. The receiver may access one or more DPs for a specificservice or restore a packet included in the corresponding DP using theinformation.

The receiver transmits information for identification of a DP to bereceived by a physical layer to a physical layer processor thatprocesses a signal and/or data in a physical layer and receives a packetstream from the corresponding DP.

The receiver performs decapsulation and header recovery on a packetstream decoded in a physical layer and transmits the packet stream to aupper layer of the receiver in the form of IP packet stream.

Then the receiver performs processing according to a protocol of a upperlayer and provides a broadcast service to the user.

FIG. 51 is a diagram illustrating processing of a broadcast signal whena logical data path includes a normal data pipe, a base data pipe, and adedicated channel according to an embodiment of the present invention.

The diagram illustrates a structure of a link layer when the logicaldata path of the physical layer includes a dedicated channel, a basedata pipe, and a normal data pipe. As described above, the link layermay include a link layer signaling part, an overhead reduction part, andan encapsulation (decapsulation) part. In this regard, a link layerprocessor to be included in the receiver may include a link layersignaling processor, an overhead reduction processor, and/or anencapsulation (decapsulation) processor. Transmission of informationoutput from each functional module (which may be embodied as hardware orsoftware) to an appropriate data path of the physical layer may be oneof main functions of the link layer.

With regard to an IP stream configured on a upper layer of a link layer,a plurality of packet streams may be transmitted according to a datarate at which data is to be transmitted, and overhead reduction andencapsulation procedures may be performed for each respectivecorresponding packet stream. A physical layer may include a data pipe(DP) as a plurality of logical data paths that a link layer can accessin one frequency band and may transmit a packet stream processed in alink layer for each respective packet stream. When the number of DPs islower than that of packet streams to be transmitted, some of the packetstreams may be multiplexed and input to a DP in consideration of a datarate.

The signaling processor may check transmission system information,related parameters, upper layer signaling, etc. and collect informationto be transmitted via signaling. Since a signal of the physical layerincludes a base DP and a normal DP, it may be efficient to transmitsignaling to the base DP in consideration of a data rate. In this case,the signaling data needs to be transmitted in the form of packetappropriate for transmission through the base DP. Signaling may beindicated using a header, etc. of a packet during link layer packetconfiguration. That is, a header of a link layer signaling packetincluding signaling data may include information indicating thatsignaling data is contained in a payload of the corresponding packet.

In a physical layer structure in which a dedicate channel and a base DPexist simultaneously, signaling information may be divided andtransmitted to the dedicated channel and the base DP. In general, sincea high data rate of the dedicated channel is not set, signalinginformation that has a small amount of signaling and needs to be rapidlyacquired may be transmitted to the dedicated channel and signaling witha high amount of signaling to the base DP. As necessary, a plurality ofdedicated channels may exist and a channel may be enable/disableaccording to a physical layer. In addition, the base DP may beconfigured with a separate structure from a normal DP. In addition, itis possible to designate one of normal DPs and use the normal DP as abase DP.

Service signaling that is transmitted in the form of IP packet in aupper layer may be transmitted to the base DP using a method such as IPaddress filtering, etc. An IP packet stream with a specific IP addressand including signaling information may be transmitted to the base DP.When a plurality of IP packet streams about corresponding servicesignaling is present, the IP packet streams may be transmitted to onebase DP using a method such as multiplexing, etc. A packet aboutdifferent service signaling may be divided into field values such as asource address and/or a port. The receiver may read information requiredfor configuration of the link layer signaling in the correspondingservice signaling packet.

When a plurality of broadcast services are transmitted through onefrequency band, the receiver may not have to decode all DPs, and it maybe efficient to pre-check the signaling information and to decode only aDP that transmits a signal and/or data associated with a requiredservice. Thus, the receiver may perform the following processors asprocessing according to a protocol of a link layer.

When a user selects or changes a service to be received, the receivertunes a corresponding frequency and reads information stored in adatabase DB, etc. with regard to a corresponding channel. Theinformation stored in the DB may include information for identificationof a dedicated channel, information for identification of a base datapipe, and/or signaling information for acquisition ofchannel/service/program.

The receiver decodes data transmitted through the dedicated channel andperforms processing associated with signaling appropriate for purpose ofthe corresponding channel. For example, a dedicated channel fortransmission of FIC may store and update information such as a serviceand/or a channel, and a dedicated channel for transmission of EAC maytransmit emergency alert information.

The receiver may acquire information of the base DP using informationtransmitted to the dedicated channel. The information transmitted to thededicated channel may include information for identification of the baseDP (e.g., an identifier of the base DP and/or an IP address of the baseDP). As necessary, the receiver may update signaling informationpre-stored in a DB of the receiver and related parameters to informationtransmitted in the dedicated channel.

The receiver may decode the base DP and acquire a link layer signalingpacket. As necessary, the link layer signaling packet may be combinedwith signaling information received from the dedicated channel. Thereceiver may find the base DP using the dedicate channel and thesignaling information pre-stored in the receiver.

The receiver acquires DP information for reception of a service selectedby a user among a plurality of DPs that are transmitted to a currentchannel and overhead reduction information about a packet stream of thecorresponding DP using the link layer signaling information. The linklayer signaling information may include information for identificationof a DP for transmission of a signal and/or data associated with aspecific service, and/or information for identification of a type ofoverhead reduction applied to a packet stream transmitted to thecorresponding DP. The receiver may access one or more DPs for a specificservice or restore a packet included in the corresponding DP using theinformation.

The receiver transmits information for identification of a DP to bereceived by a physical layer to a physical layer processor thatprocesses a signal and/or data in a physical layer and receives a packetstream from the corresponding DP.

The receiver performs decapsulation and header recovery on a packetstream decoded in a physical layer and transmits the packet stream to aupper layer of the receiver in the form of IP packet stream.

Then the receiver performs processing according to a protocol of a upperlayer and provides a broadcast service to the user.

According to an embodiment of the present invention, when informationfor service signaling is transmitted by one or more IP packet streams,the IP packet streams may be multiplexed and transmitted as one base DP.The receiver may distinguish between packets for different servicesignaling through a field of a source address and/or a port. Thereceiver may read out information for acquiring/configuring link layersignaling from a service signaling packet.

In the process of processing signaling information transmitted throughthe dedicated channel, the receiver may obtain version information ofthe dedicated channel or information identifying whether update has beenperformed and, if it is judged that there is no change in the signalinginformation in the dedicated channel, the receiver may omit processing(decoding or parsing) of the signaling information transmitted throughthe dedicated channel. If it is confirmed that the dedicated channel hasnot been updated, the receiver may acquire information of a base DPusing prestored information.

In the above-described process of acquiring the DP information for aservice selected by the user and the overhead reduction informationabout the DP packet stream transmitting the corresponding service, ifthe information about the DP transmitting the service selected by theuser is transmitted through upper layer signaling (e.g., a layer higherthan a link layer, or an IP layer), the receiver may acquire thecorresponding information from the DB, the buffer, and/or the sharedmemory as described above and use the acquired information asinformation about a DP requiring decoding.

If link layer signaling (link layer signaling information) and normaldata (e.g., broadcast content data) is transmitted through the same DPor if only type of DP is used in a broadcast system, the normal datatransmitted through the DP may be temporarily stored in the buffer orthe memory while the signaling information is decoded and parsed. Uponacquiring the signaling information, the receiver may transmit a commandfor extracting a DP that should be obtained according to thecorresponding signaling information to a device for extracting andprocessing the DP by a method using system interior command words.

FIG. 52 is a diagram illustrating a detailed processing operation of asignal and/or data in a link layer of a receiver when a logical datapath includes a normal data pipe, a base data pipe, and a dedicatedchannel according to an embodiment of the present invention.

The present embodiment considers a situation in which one or moreservices provided by one or more broadcasters are transmitted in onefrequency band. It may be considered that one broadcaster transmits oneor more broadcast services, one service includes one or more componentsand a user receives content in units of broadcast services. In addition,some of one or more components included in one broadcast service may bereplaced with other components according to user selection.

A fast information channel (FIC) and/or emergency alert channel (EAC)may be transmitted to a dedicated channel. A base DP and a normal DP maybe differentiated in a broadcast signal and transmitted or managed.Configuration information of the FIC and/or the EAC may be transmittedthrough physical layer signaling so as to notify the receiver of the FICand/or the EAC, and the link layer may format signaling according to thecharacteristic of the corresponding channel. Transmission of data to aspecific channel of a physical layer is performed from a logical pointof view and an actual operation may be performed according to thecharacteristic of a physical layer.

Information about a service of each broadcaster, transmitted in acorresponding frequency, and information about a path for reception ofthe service may be transmitted through the FIC. To this end, thefollowing information may be provided (signaled) via link layersignaling.

System Parameter: Transmitter related parameter, and/or parameterrelated to a broadcaster that provides a service in a correspondingchannel.

Link layer: which includes context information associated with IP headercompression and/or ID of a DP to which corresponding context is applied.

Upper layer: IP address and/or UDP port number, service and/or componentinformation, emergency alert information, and mapping relationinformation between a DP and an IP address of a packet streamtransmitted in an IP layer.

When a plurality of broadcast services is transmitted through onefrequency band, a receiver may not have to decode all DPs, and it may beefficient to pre-check signaling information and to decode only a DPabout a required service. In a broadcast system, a transmitter maytransmit information for identification of only a required DP through anFIC, and the receiver may check a DP to be accessed for a specificserviced, using the FIC. In this case, an operation associated with thelink layer of the receiver may be performed as follows.

When a user selects or changes a service to be received by a user, thereceiver tunes a corresponding frequency and reads information of areceiver, stored in a DB, etc. in regard to a corresponding channel. Theinformation stored in the DB of the receiver may be configured byacquiring an FIC during initial channel scan and using informationincluded in the FIC.

The receiver may receive an FIC and update a pre-stored DB or acquireinformation about a component about a service selected by the user andinformation about a mapping relation for DPs that transmit componentsfrom the FIC. In addition, the information about a base DP thattransmits signaling may be acquired from the FIC.

When initialization information related to robust header compression(RoHC) is present in signaling transmitted through the FIC, the receivermay acquire the initialization information and prepare header recovery.

The receiver decodes a base DP and/or a DP that transmits a serviceselected by a user based on information transmitted through the FIC.

The receiver acquires overhead reduction information about a DP that isbeing received, included in the base DP, performs decapsulation and/orheader recovery on a packet stream received in a normal DP using theacquired overhead information, and transmits the packet stream to aupper layer of the receiver in the form of IP packet stream.

The receiver may receive service signaling transmitted in the form of IPpacket with a specific address through a base DP and transmit the packetstream to the upper layer with regard to a received service.

When emergency alert occurs, in order to rapidly transmit an emergencyalert message to a user, the receiver receives signaling informationincluded in a CAP message through signaling, parses the signalinginformation, and immediately transmits the signaling information to auser, and finds a path for reception of a corresponding service andreceives service data when information of a path through which anaudio/video service can be received via signaling can be confirmed. Inaddition, when information transmitted through a broadband and so on ispresent, an NRT service and additional information are received usingcorresponding uniform resource identifier (URI) information and so on.Signaling information associated with emergency alert will be describedbelow in detail.

The receiver processes the emergency alert as follows.

The receiver recognizes a situation in which an emergency alert messageis transmitted through a preamble and so on of a physical layer. Thepreamble of the physical layer may be a signaling signal included in abroadcast signal and may correspond to signaling in the physical layer.The preamble of the physical layer may mainly include information foracquisition of data, a broadcast frame, a data pipe, and/or atransmission parameter that are included in a broadcast signal.

The receiver checks configuration of an emergency alert channel (EAC)through physical layer signaling of the receiver and decodes the EAC toacquire EAT. Here, the EAC may correspond to the aforementioneddedicated channel.

The receiver checks the received EAT, extracts a CAP message, andtransmits the CAP message to a CAP parser.

The receiver decodes a corresponding DP and receives service data whenservice information associated with the emergency alert is present inthe EAT. The EAT may include information for identification of a DP fortransmitting a service associated with the emergency alert.

When information associated with NRT service data is present in the EATor the CAP message, the receiver receives the information through abroadband.

FIG. 53 is a diagram illustrating syntax of a fast information channel(FIC) according to an embodiment of the present invention.

Information included in the FIC may be transmitted in the form of fastinformation table (FIT).

Information included in the FIT may be transmitted in the form of XMLand/or section table.

The FIT may include table_id information, FIT_data_version information,num_broadcast information, broadcast_id information, delivery_system_idinformation, base_DP_id information, base_DP_version information,num_service information, service_id information, service_categoryinformation, service_hidden_flag information, SP_indicator information,num_component information, component_id information, DP_id information,context_id information, RoHC_init_descriptor, context profileinformation, max_cid information, and/or large_cid information.

The table_id information indicates that a corresponding table sectionrefers to fast information table.

The FIT_data_version information may indicate version information aboutsyntax and semantics contained in the fast information table. Thereceiver may determine whether signaling contained in the correspondingfast information table is processed, using the FIT_data_versioninformation. The receiver may determine whether information ofpre-stored FIC is updated, using the information.

The num_broadcast information may indicate the number of broadcastersthat transmit a broadcast service and/or content through a correspondingfrequency or a transmitted transport frame.

The broadcast_id information may indicate a unique identifier of abroadcaster that transmits a broadcast service and/or content through acorresponding frequency or a transmitted transport frame. In the case ofa broadcaster that transmits MPEG-2 TS-based data, broadcast_id may havea value such as transport_stream_id of MPEG-2 TS.

The delivery_system_id information may indicate an identifier for abroadcast transmission system that applies and processes the sametransmission parameter on a broadcast network that performstransmission.

The base_DP_id information is information for identification of a baseDP in a broadcast signal. The base DP may refer to a DP that transmitsservice signaling including overhead reduction and/or program specificinformation/system information (PSI/SI) of a broadcaster correspondingto broadcast_id. Alternatively, the base_DP_id information may refer toa representative DP that can decode a component included in a broadcastservice in the corresponding broadcaster.

The base_DP_version information may refer to version information aboutdata transmitted through a base DP. For example, when service signalingsuch as PSI/SI and so on is transmitted through the base DP, if servicesignaling is changed, a value of the base_DP_version information may beincreased one by one.

The num_service information may refer to the number of broadcastservices transmitted from a broadcaster corresponding to thebroadcast_id in a corresponding frequency or a transport frame.

The service_id information may be used as an identifier foridentification of a broadcast service.

The service_category information may refer to a category of a broadcastservice. According to a value of a corresponding field, theservice_category information may have the following meaning. When avalue of the service_category information is 0x01, the service_categoryinformation may refer to a basic TV, when the value of theservice_category information is 0x02, the service_category informationmay refer to a basic radio, when the value of the service_categoryinformation is 0x03, the service_category information may refer to an RIservice, when the value of the service_category information is 0x08, theservice_category information may refer to a service guide, and when thevalue of the service_category information is 0x09, the service_categoryinformation may refer to emergency alerting.

The service_hidden_flag information may indicate whether a correspondingbroadcast service is hidden. When the service is hidden, the broadcastservice may be a test service or a self-used service and may beprocessed to be disregarded or hidden from a service list by a broadcastreceiver.

The SP_indicator information may indicate whether service protection isapplied to one or more components in a corresponding broadcast service.

The num_component information may indicate the number of componentsincluded in a corresponding broadcast service.

The component_id information may be used as an identifier foridentification of a corresponding component in a broadcast service.

The DP_id information may be used as an identifier indicating a DP thattransmits a corresponding component.

The RoHC_init_descriptor may include information associated withoverhead reduction and/or header recovery. The RoHC_init_descriptor mayinclude information for identification of a header compression methodused in a transmission terminal.

The context_id information may represent a context corresponding to afollowing RoHC related field. The context_id information may correspondto a context identifier (CID).

The context_profile information may represent a range of a protocol forcompression of a header in RoHC. When a compressor and a decompressorhave the same profile, it is possible to compress and restore a streamin the RoHC.

The max_cid information is used for indicating a maximum value of a CIDto a decompressor.

The large_cid information has a boolean value and indicates whether ashort CID (0 to 15) or an embedded CID (0 to 16383) is used for CIDconfiguration. Accordingly, the sized of byte for representing the CIDis determined together.

FIG. 54 is a diagram illustrating syntax of an emergency alert table(EAT) according to an embodiment of the present invention.

Information associated with emergency alert may be transmitted throughthe EAC. The EAC may correspond to the aforementioned dedicated channel.

The EAT according to an embodiment of the present invention may includeEAT_protocol_version information, automatic_tuning_flag information,num_EAS_messages information, EAS_message_id information,EAS_IP_version_flag information, EAS_message_transfer_type information,EAS_message_encoding_type information, EAS_NRT_flag information,EAS_message_length information, EAS_message_byte information, IP_addressinformation, UDP_port_num information, DP_id information,automatic_tuning_channel_number information, automatic_tuning_DP_idinformation, automatic_tuning_service_id information, and/orEAS_NRT_service_id information.

The EAT_protocol_version information indicates a protocol version ofreceived EAT.

The automatic_tuning_flag information indicates whether a receiverautomatically performs channel conversion.

The num_EAS_messages information indicates the number of messagescontained in the EAT.

The EAS_message_id information is information for identification of eachEAS message.

The EAS_IP_version_flag information indicates IPv4 when a value of theEAS_IP_version_flag information is 0, and indicates IPv6 when a value ofthe EAS_IP_version_flag information is 1.

The EAS_message_transfer_type information indicates the form in which anEAS message is transmitted. When a value of theEAS_message_transfer_type information is 000, theEAS_message_transfer_type information indicates a not specified state,when a value of the EAS_message_transfer_type information is 001, theEAS_message_transfer_type information indicates a no alert message (onlyAV content), and when a value of the EAS_message_transfer_typeinformation is 010, the EAS_message_transfer_type information indicatesthat an EAS message is contained in corresponding EAT. To this end, alength field and a field about the corresponding EAS message are added.When a value of the EAS_message_transfer_type information is 011, theEAS_message_transfer_type information indicates that the EAS message istransmitted through a data pipe. The EAS may be transmitted in the formof IP datagram in a data pipe. To this end, IP address, UDP portinformation, and DP information of a transmitted physical layer may beadded.

The EAS_message_encoding_type information indicates information about anencoding type of an emergence alert message. For example, when a valueof the EAS_message_encoding_type information is 000, theEAS_message_encoding_type information indicates a not specific state,when a value of the EAS_message_encoding_type information is 001, theEAS_message_encoding_type information indicates No Encoding, when avalue of the EAS_message_encoding_type information is 010, theEAS_message_encoding_type information indicates DEFLATE algorithm(RFC1951), and 001 to 111 among values of the EAS_message_encoding_typeinformation may be reserved for other encoding types.

The EAS_NRT_flag information indicates whether NRT contents and/or NRTdata associated with a received message is present. When a value of theEAS_NRT_flag information is 0, the EAS_NRT_flag information indicatesthat NRT contents and/or NRT data associated with a received emergencymessage is not present, and when a value of the EAS_NRT_flag informationis 1, the EAS_NRT_flag information indicates that NRT contents and/orNRT data associated with a received emergency message is present.

The EAS_message_length information indicates a length of an EAS message.

The EAS_message_byte information includes content of an EAS message.

The IP_address information indicates an IP address of an IP address fortransmission of an EAS message.

The UDP_port_num information indicates a UDP port number fortransmission of an EAS message.

The DP_id information identifies a data pipe that transmits an EASmessage.

The automatic_tuning_channel_number information includes informationabout a number of a channel to be converted.

The automatic_tuning_DP_id information is information for identificationof a data pipe that transmits corresponding content.

The automatic_tuning_service_id information is information foridentification of a service to which corresponding content belongs.

The EAS_NRT_service_id information is information for identification ofan NRT service corresponding to the case in which NRT contents and dataassociated with a received emergency alert message and transmitted, thatis, the case in which an EAS_NRT_flag is enabled.

FIG. 55 is a diagram illustrating a packet transmitted to a data pipeaccording to an embodiment of the present invention.

According to an embodiment of the present invention, configuration of apacket in a link layer is newly defined so as to generate a compatiblelink layer packet irrespective of change in protocol of a upper layer orthe link layer or a lower layer of the link layer.

The link layer packet according to an embodiment of the presentinvention may be transmitted to a normal DP and/or a base DP.

The link layer packet may include a fixed header, an expansion header,and/or a payload.

The fixed header is a header with a fixed size and the expansion headeris a header, the size of which can be changed according to configurationof the packet of the upper layer. The payload is a region in which dataof the upper layer is transmitted.

A header (the fixed header or the expansion header) of a packet mayinclude a field indicating a type of the payload of the packet. In thecase of the fixed header, first 3 bits (packet type) of 1 byte mayinclude data for identification of a packet type of the upper layer, andthe remaining 5 bits may be used as an indicator part. The indicatorpart may include data for identification of a configuring method of apayload and/or configuration information of the expansion header and maybe changed according to a packet type.

A table shown in the diagram represents a type of a upper layer includedin a payload according to a value of a packet type.

According to system configuration, an IP packet and/or an RoHC packet ofthe payload may be transmitted through a DP, and a signaling packet maybe transmitted through a base DP. Accordingly, when a plurality ofpackets are mixed and transmitted, packet type values may also beapplied so as to differentiate a data packet and a signaling packet.

When a packet type value is 000, an IP packet of IPv4 is included in apayload.

When a packet type value is 001, an IP packet of IPv6 is included in apayload.

When a packet type value is 010, a compressed IP packet is included in apayload. The compressed IP packet may include an IP packet to whichheader compression is applied.

When a packet type value is 110, a packet including signaling data isincluded in a payload.

When a packet type value is 111, a framed packet type is included in apayload.

FIG. 56 is a diagram illustrating a detailed processing operation of asignal and/or data in each protocol stack of a transmitter when alogical data path of a physical layer includes a dedicated channel, abase DP, and a normal data DP, according to another embodiment of thepresent invention.

In one frequency band, one or more broadcasters may provide broadcastservices. A broadcaster transmits multiple broadcast services and onebroadcast service may include one or more components. A user may receivecontent in units of broadcast services.

In a broadcast system, a session-based transmission protocol may be usedto support IP hybrid broadcast and the contents of signaling deliveredto each signaling path may be determined according to the structure ofthe corresponding transmission protocol.

As described above, data related to the FIC and/or the EAC may betransmitted/received over the dedicated channel. In the broadcastsystem, a base DP and a normal DP may be used to distinguishtherebetween.

Configuration information of the FIC and/or EAC may be included inphysical layer signaling (or a transmission parameter). A link layer mayformat signaling according to characteristics of a correspondingchannel. Transmission of data to a specific channel of a physical layermay be performed from a logical point of view and actual operation maybe performed according to characteristics of a physical layer.

The FIC may include information about services of each broadcaster,transmitted in a corresponding frequency and information about paths forreceiving the services. The FIC may include information for serviceacquisition and may be referred to as service acquisition information.

The FIC and/or the EAC may be included in link layer signaling.

Link layer signaling may include the following information.

System Parameter—A parameter related to a transmitter or a parameterrelated to a broadcaster that provides a service in a correspondingchannel.

Link layer: Context information associated with IP header compressionand an ID of a DP to which a corresponding context is applied.

Upper layer: IP address and UDP port number, service and componentinformation, emergency alert information, and a mapping relationshipbetween an ID address, a UDP port number, a session ID, and a DP of apacket stream and signaling transmitted in an IP layer.

As described above, one or more broadcast services are transmitted inone frequency band, the receiver does not need to decode all DPs and itis efficient to pre-check signaling information and to decode only a DPrelated to a necessary service.

In this case, referring to the drawing, the broadcast system may provideand acquire information for mapping a DP and a service, using the FICand/or the base DP.

A process of processing a broadcast signal or broadcast data in atransmitter of the drawing will now be described. One or morebroadcasters (broadcasters #1 to # N) may process component signalingand/or data for one or more broadcast services so as to be transmittedthrough one or more sessions. One broadcast service may be transmittedthrough one or more sessions. The broadcast service may include one ormore components included in the broadcast service and/or signalinginformation for the broadcast service. Component signaling may includeinformation used to acquire components included in the broadcast servicein a receiver. Service signaling, component signaling, and/or data forone or more broadcast services may be transmitted to a link layerthrough processing in an IP layer.

In the link layer, the transmitter performs overhead reduction whenoverhead reduction for an IP packet is needed and generates relatedinformation as link layer signaling. Link layer signaling may include asystem parameter specifying the broadcast system, in addition to theabove-described information. The transmitter may process an IP packet ina link layer processing procedure and transmit the processed IP packetto a physical layer in the form of one or more DPs.

The transmitter may transmit link layer signaling to the receiver in theform or configuration of an FIC and/or an EAC. Meanwhile, thetransmitter may also transmit link layer signaling to the base DPthrough an encapsulation procedure of the link layer.

FIG. 57 is a diagram illustrating a detailed processing operation of asignal and/or data in each protocol stack of a receiver when a logicaldata path of a physical layer includes a dedicated channel, a base DP,and a normal data DP, according to another embodiment of the presentinvention.

If a user selects or changes a service desired to be received, areceiver tunes to a corresponding frequency. The receiver readsinformation stored in a DB etc. in association with a correspondingchannel. The information stored in the DB etc. of the receiver may beinformation included upon acquiring an FIC and/or an EAC during initialchannel scan. Alternatively, the receiver may extract transmittedinformation as described above in this specification.

The receiver may receive the FIC and/or the EAC, receive informationabout a channel that the receiver desires to access, and then updateinformation pre-stored in the DB. The receiver may acquire componentsfor a service selected by a user and information about a mappingrelationship of a DP transmitted by each component or acquire a base DPand/or a normal DP through which signaling necessary to obtain suchinformation is transmitted. Meanwhile, when it is judged that there isno change in corresponding information using version information of theFIC or information identifying whether to require additional update of adedicated channel, the receiver may omit a procedure of decoding orparsing the received FIC and/or EAC.

The receiver may acquire a link layer signaling packet including linklayer signaling information by decoding a base DP and/or a DP throughwhich signaling information is transmitted, based on informationtransmitted through the FIC. The receiver may use, when necessary, thereceived link layer signaling information by a combination withsignaling information (e.g., receiver information in the drawing)received through the dedicated channel.

The receiver may acquire information about a DP for receiving a serviceselected by the user among multiple DPs that are being transmitted overa current channel and overhead reduction information about a packetstream of the corresponding DP, using the FIC and/or the link layersignaling information.

When the information about the DP for receiving the selected service istransmitted through upper layer signaling, the receiver may acquiresignaling information stored in the DB and/or the shared memory asdescribed above and then acquire information about a DP to be decoded,indicated by the corresponding signaling information.

When the link layer signaling information and normal data (e.g., dataincluded in broadcast content) are transmitted through the same DP oronly one DP is used for transmission of the link layer signalinginformation and normal data, the receiver may temporarily store thenormal data transmitted through the DP in a device such as a bufferwhile the signaling information is decoded and/or parsed.

The receiver may acquire the base DP and/or the DP through which thesignaling information is transmitted, acquire overhead reductioninformation about a DP to be received, perform decapsulation and/orheader recovery for a packet stream received in a normal DP, using theacquired overhead information, process the packet stream in the form ofan IP packet stream, and transmit the IP packet stream to a upper layerof the receiver.

FIG. 58 is a diagram illustrating a syntax of an FIC according toanother embodiment of the present invention.

Information included in the FIC described in this drawing may beselectively combined with other information included in the FIC and mayconfigure the FIC.

The receiver may rapidly acquire information about a channel, using theinformation included in the FIC. The receiver may acquire bootstraprelated information using the information included in the FIC. The FICmay include information for fast channel scan and/or fast serviceacquisition. The FIC may be referred to by other names, for example, aservice list table or service acquisition information. The FIC may betransmitted by being included in an IP packet in an IP layer accordingto a broadcast system. In this case, an IP address and/or a UDP portnumber, transmitting the FIC, may be fixed to specific values and thereceiver may recognize that the IP packet transmitted with thecorresponding IP address and/or UDP port number includes the FIC,without an additional processing procedure.

The FIC may include FIC_protocol_version information,transport_stream_id information, num_partitions information,partition_id information, partition_protocol_version information,num_services information, service_id information, service_data_versioninformation, service_channel_number information, service_categoryinformation, service_status information, service_distributioninformation, sp_indicator information, IP_version_flag information,SSC_source_IP_address_flag information, SSC_source_IP_addressinformation, SSC_destination_IP_address information,SSC_destination_UDP_port information, SSC_TSI information, SSC_DP_IDinformation, num_partition_level_descriptors information,partition_level_descriptor( ) information, num_FIC_level_descriptorsinformation, and/or FIC_level_descriptor( ) information.

FIC_protocol_version information represents a version of a protocol ofan FIC.

transport_stream_id information identifies a broadcast stream.transport_stream_id information may be used as information foridentifying a broadcaster.

num_partitions information represents the number of partitions in abroadcast stream. The broadcast stream may be transmitted after beingdivided into one or more partitions. Each partition may include one ormore DPs. The DPs included in each partition may be used by onebroadcaster. In this case, the partition may be defined as a datatransmission unit allocated to each broadcaster.

partition_id information identifies a partition. partition_idinformation may identify a broadcaster.

partition_protocol_version information represents a version of aprotocol of a partition.

num_services information represents the number of services included in apartition. A service may include one or more components.

service_id information identifies a service.

service_data_version information represents change when a signalingtable (signaling information) for a service is changed or a serviceentry for a service signaled by an FIC is changed. service_data_versioninformation may increment a value thereof whenever such change ispresent.

service_channel_number information represents a channel number of aservice.

service_category information represents a category of a service. Thecategory of a service includes A/V content, audio content, an electronicservice guide (ESG), and/or content on demand (CoD).

service_status information represents a state of a service. A state of aservice may include an active or suspended state and a hidden or shownstate. The state of a service may include an inactive state. In theinactive state, broadcast content is not currently provided but may beprovided later. Accordingly, when a viewer scans a channel in areceiver, the receiver may not show a scan result for a correspondingservice to the viewer.

service_distribution information represents a distribution state of datafor a service. For example, service_distribution information mayrepresent that entire data of a service is included in one partition,partial data of a service is not included in a current partition butcontent is presentable only by data in this partition, another partitionis needed to present content, or another broadcast stream is needed topresent content.

sp_indicator information identifies whether service protection has beenapplied. sp_indicator information may identify, for example, formeaningful presentation, whether one or more necessary components areprotected (e.g., a state in which a component is encrypted).

IP_version_flag information identifies whether an IP address indicatedby SSC_source_IP_address information and/or SSC destination IP addressinformation is an IPv4 address or an IPv6 address.

SSC_source_IP_address flag information identifies whetherSSC_source_IP_address information is present.

SSC_source_IP_address information represents a source IP address of anIP datagram that transmits signaling information for a service. Thesignaling information for a service may be referred to as service layersignaling. Service layer signaling includes information specifying abroadcast service. For example, service layer signaling may includeinformation identifying a data unit (a session, a DP, or a packet) thattransmits components constituting a broadcast service.

SSC_destination_IP_address information represents a destination IPaddress of an IP datagram (or channel) that transmits signalinginformation for a service.

SSC_destination_UDP_port information represents a destination UDP portnumber for a UDP/IP stream that transmits signaling information for aservice.

SSC_TSI information represents a transport session identifier (TSI) ofan LCT channel (or session) that transmits signaling information (or asignaling table) for a service.

SSC_DP_ID information represents an ID for identifying a DP includingsignaling information (or a signaling table) for a service. As a DPincluding the signaling information, the most robust DP in a broadcasttransmission process may be allocated.

num_partition_level_descriptors information identifies the number ofdescriptors of a partition level for a partition.

partition_level_descriptor( ) information includes zero or moredescriptors that provide additional information for a partition.

num_FIC_level_descriptors information represents the number ofdescriptors of an FIC level for an FIC.

FIC_level_descriptor( ) information includes zero or more descriptorsthat provide additional information for an FIC.

FIG. 59 is a diagram illustrating signaling_Information_Part( )according to an embodiment of the present invention.

A broadcast system may add additional information to an extended headerpart in the case of a packet for transmitting signaling information in astructure of a packet transmitted through the above-described DP. Suchadditional information will be referred to asSignaling_Information_Part( ).

Signaling_Information_Part( ) may include information used to determinea processing module (or processor) for received signaling information.In a system configuration procedure, the broadcast system may adjust thenumber of fields indicating information and the number of bits allocatedto each field, in a byte allocated to Signaling_Information_Part( ).When signaling information is transmitted through multiplexing, areceiver may use information included in Signaling_Information_Part( )to determine whether corresponding signaling information is processedand determine to which signaling processing module signaling informationshould be transmitted.

Signaling_Information_Part( ) may include Signaling_Class information,Information_Type information, and/or signaling format information.

Signaling_Class information may represent a class of transmittedsignaling information. Signaling information may correspond to an FIC,an EAC, link layer signaling information, service signaling information,and/or upper layer signaling information. Mapping for a class ofsignaling information indicated by each value of configuration of thenumber of bits of a field of Signaling Class information may bedetermined according to system design.

Information_Type information may be used to indicate details ofsignaling information identified by signaling class information. Meaningof a value indicated by Information_Type information may be additionallydefined according to class of signaling information indicated bySignaling_Class information.

Signaling format information represents a form (or format) of signalinginformation configured in a payload. The signaling format informationmay identify formats of different types of signaling informationillustrated in the drawing and identify a format of additionallydesignated signaling information.

Signaling_Information_Part( ) of (a) and (b) illustrated in the drawingis one embodiment and the number of bits allocated to each field thereofmay be adjusted according to characteristics of the broadcast system.

Signaling_Information_Part( ) as in (a) of the drawing may includesignaling class information and/or signaling format information.Signaling_Information_Part( ) may be used when a type of signalinginformation need not be designated or an information type can be judgedin signaling information. Alternatively, when only one signaling formatis used or when an additional protocol for signaling is present so thatsignaling formats are always equal, only a 4-bit signaling class fieldmay be used without configuring a signaling field and the other fieldsmay be reserved for later use or an 8-bit signaling class maybeconfigured to support various types of signaling.

Signaling_Information_Part( ) as in (b) of the drawing may furtherinclude information type information for indicating a type orcharacteristic of more detailed information in a signaling class whenthe signaling class is designated and may also include signaling formatinformation. Signaling class information and information typeinformation may be used to determine decapsulation of signalinginformation or a processing procedure of corresponding signaling. Adetailed structure or processing of link layer signaling may refer tothe above description and a description which will be given below.

FIG. 60 is a diagram illustrating a procedure for controlling anoperation mode of a transmitter and/or a receiver in a link layeraccording to an embodiment of the present invention.

When the operation mode of the transmitter or the receiver of the linklayer is determined, a broadcast system can be more efficiently used andcan be flexibly designed. The method of controlling the link layer modeproposed according to the present invention can dynamically convert amode of a link layer in order to efficiently manage a system bandwidthand processing time. In addition, the method of controlling the linklayer mode according to the present invention may easily cope with thecase in which a specific mode needs to be supported due to change in aphysical layer or on the other hand, the specific mode does not have tobe changed any more. In addition, the method of controlling the linklayer mode according to the present invention may also allow a broadcastsystem to easily satisfy requirements of a corresponding broadcasterwhen a broadcaster providing a broadcast service intends to designate amethod of transmitting a corresponding service.

The method of controlling the mode of the link layer may be configuredto be performed only in a link layer or to be performed via change indata configuration in the link layer. In this case, it is possible toperform an independent operation of each layer in a network layer and/ora physical layer without embodiment of a separate function. In the modeof the link layer proposed according to the present invention, it ispossible to control the mode with signaling or parameters in a systemwithout changing a system in order to satisfy configuration of aphysical layer. A specific mode may be performed only when processing ofcorresponding input is supported in a physical layer.

The diagram is a flowchart illustrating processing of signal and/or datain an IP layer, a link layer, and a physical layer by a transmitterand/or a receiver.

A function block (which may be embodied as hardware and/or software) formode control may be added to the link layer and may manage parameterand/or signaling information for determination of whether a packet isprocessed. The link layer may determine whether a corresponding functionis performed during processing of a packet stream using information of amode control functional block.

First, an operation of the transmitter will be described.

When an IP is input to a link layer, the transmitter determines whetheroverhead reduction (j16020) is performed using a mode control parameter(j16005). The mode control parameter may be generated by a serviceprovider in the transmitter. The mode control parameter will bedescribed below in detail.

When the overhead reduction (j16020) is performed, information aboutoverhead reduction is generated and is added to link layer signaling(j16060) information. The link layer signaling (j16060) information mayinclude all or some of mode control parameters. The link layer signaling(j16060) information may be transmitted in the form of link layersignaling packet. The link layer signaling packet may be mapped to a DPand transmitted to the receiver, but may not be mapped to the DP and maybe transmitted to the receiver in the form of link layer signalingpacket through a predetermined region of a broadcast signal.

A packet stream on which the overhead reduction (j16020) is performed isencapsulated (j16030) and input to a DP of a physical layer (j16040).When overhead reduction is not performed, whether encapsulation isperformed is re-determined (j16050).

A packet stream on which the encapsulation (j16030) is performed isinput to a DP (j16040) of a physical layer. In this case, the physicallayer performs an operation for processing a general packet (a linklayer packet). When overhead reduction and encapsulation are notperformed, an IP packet is transmitted directly to a physical layer. Inthis case, the physical layer performs an operation for processing theIP packet. When the IP packet is directly transmitted, a parameter maybe applied to perform the operation only when the physical layer supportIP packet input. That is, a value of a mode control parameter may beconfigured to be adjusted such that a process of transmitting an IPpacket directly to a physical layer is not performed when the physicallayer does not support processing of an IP packet.

The transmitter transmits a broadcast signal on which this process isperformed, to the receiver.

An operation of the receiver will be described below.

When a specific DP is selected for the reason such channel change and soon according to user manipulation and a corresponding DP receives apacket stream (j16110), the receiver may check a mode in which a packetis generated, using a header and/or signaling information of the packetstream (j16120). When the operation mode during transmission of thecorresponding DP is checked, decapsulation (j16130) and overheadreduction (j16140) processes are performed through a receiving operatingprocess of a link layer and then an IP packet is transmitted to a upperlayer. The overhead reduction (j16140) process may include an overheadrecovery process.

FIG. 61 is a diagram illustrating an operation in a link layer accordingto a value of a flag and a type of a packet transmitted to a physicallayer according to an embodiment of the present invention.

In order to determine an operation mode of the link layer, theaforementioned signaling method may be used. Signaling informationassociated with the method may be transmitted directly to a receiver. Inthis case, the aforementioned signaling data or link layer signalingpacket may include mode control that will be described below and relatedinformation.

In consideration of the complexity of the receiver, an operation mode ofthe link layer may be indirectly indicated to the receiver.

The following two flags may be configured with regard to control of anoperation mode.

-   -   Header compression flag (HCF): This may be a flag for        determination of whether header compression is applied to a        corresponding link layer and may have a value indicating enable        or disable.    -   Encapsulation flag (EF): This may be a flag for determination of        whether encapsulation is applied in a corresponding link layer        and may have a value indicating enable or disable. However, when        encapsulation needs to be performed according to a header        compression scheme, the EF may be defined to be dependent upon a        HCF.

A value mapped to each flag may be applied according to systemconfiguration as long as the value represents Enable and Disable, and abit number allocated to each flag can be changed. According to anembodiment of the present invention, an enable value may be mapped to 1and a disable value may be mapped to 0.

The diagram shows whether header compression and encapsulation includedin a link layer are performed according to values of HCF and EF and inthis case, a packet format transmitted to a physical layer. That is,according to an embodiment of the present invention, the receiver canknow a type of a packet input to the physical layer as information aboutthe HCF and the EF.

FIG. 62 is a diagram a descriptor for signaling a mode control parameteraccording to an embodiment of the present invention.

Flags as information about mode control in a link layer may be signalinginformation, generated by the transmitter in the form of descriptor, andtransmitted to the receiver. Signaling including a flag as informationabout mode control may be used to control an operation mode in atransmitter of a headend terminal, and whether a flag as informationabout mode control is included in signaling transmitted to the receivermay be optionally selected.

When signaling including a flag as information about mode control istransmitted to the receiver, the receiver may directly select anoperation mode about a corresponding DP and perform a packetdecapsulation operation. When signaling including a flag as informationabout mode control is not transmitted to the receiver, the receiver candetermine a mode in which the signaling is transmitted, using physicallayer signaling or field information of a packet header, which istransmitted to the receiver.

The link layer mode control description according to an embodiment ofthe present invention may include DP_id information, HCF information,and/or EF information. The link layer mode control description may beincluded in a transmission parameter in the aforementioned FIC, linklayer signaling packet, signaling via a dedicated channel, PSI/SI,and/or physical layer.

The DP_id information identifies a DP to which a mode in a link layer isapplied.

The HCF information identifies whether header compression is applied inthe DP identified by the DP_id information.

The EF information identifies whether encapsulation is performed on theDP identified by the DP_id information.

FIG. 63 is a diagram illustrating an operation of a transmitter forcontrolling a operation mode according to an embodiment of the presentinvention.

Although not illustrated in the diagram, prior to a processing processof al ink layer, a transmitter may perform processing in a upper layer(e.g., an IP layer). The transmitter may generate an IP packet includingbroadcast data for a broadcast service.

The transmitter parses or generates a system parameter (JS19010). Here,the system parameter may correspond to the aforementioned signaling dataand signaling information.

The transmitter may receive or set mode control related parameter orsignaling information during a broadcast data processing process in alink layer and sets a flag value associated with operation mode control(JS19020). The transmitter may perform this operation after the headercompression operation or the encapsulation operation. That is, thetransmitter may perform the header compression or encapsulationoperation and generate information associated with this operation.

The transmitter acquires a packet of a upper layer that needs to betransmitted through a broadcast signal (JS19030). Here, the packet ofthe upper layer may correspond to an IP packet.

The transmitter checks HCF in order to determine whether headercompression is applied to the packet of the upper layer (JS19040).

When the HCF is enabled, the transmitter applies the header compressionto the packet of the upper layer (JS19050). After header compression isperformed, the transmitter may generate the HCF. The HCF may be used tosignal whether header compression is applied, to the receiver.

The transmitter performs encapsulation on the packet of the upper layerto which header compression is applied to generate a link layer packet(JS19060). After the encapsulation process is performed, the transmittermay generate an EF. The EF may be used to signal whether encapsulationis applied to the upper layer packet, to the receiver.

The transmitter transmits the link layer packet to a physical layerprocessor (JS19070). Then the physical layer processor generates abroadcast signal including the link layer packet and transmits thebroadcast signal to the receiver.

When the HCF is disabled, the transmitter checks the EF in order todetermine whether encapsulation is applied (JS19080).

When the EF is enabled, the transmitter performs encapsulation on theupper layer packet (JS19090). When the EF is disabled, the transmitterdoes not perform separate processing on the corresponding packet stream.The transmitter transmits the packet stream (link layer packet) on whichprocessing is completed in the link layer, to a physical layer(JS19070). Header compression, encapsulation, and/or generation of linklayer may be performed by a link layer packet generator (i.e. link layerprocessor) in the transmitter.

The transmitter may generate service signaling channel (SCC) data. Theservice signaling channel data may be generated by a service signalingdata encoder. The service signaling data encoder may be included in alink layer processor and may present separately from the link layerprocessor. The service signaling channel data may include theaforementioned FIC and/or EAT. The service signaling channel data may betransmitted to the aforementioned dedicated channel.

FIG. 64 is a diagram illustrating an operation of a receiver forprocessing a broadcast signal according to an operation mode accordingto an embodiment of the present invention.

A receiver may receive information associated with an operation mode ina link layer together with a packet stream.

The receiver receives signaling information and/or channel information(JS20010). Here, a description of the signaling information and/or thechannel information is replaced with the above description.

The receiver selects a DP for receiving and processing according to thesignaling information and/or the channel information (JS20020).

The receiver performs decoding of a physical layer on the selected DPand receives a packet stream of a link layer (JS20030).

The receiver checks whether link layer mode control related signaling isincluded in the received signaling (JS20040).

When the receiver receives the link layer mode related information, thereceiver checks an EF (JS20050).

When the EF is enabled, the receiver performs a decapsulation process ona link layer packet (JS20060).

The receiver checks an HCF after decapsulation of the packet, andperforms a header decompression process when the HCF is enabled(JS20080).

The receiver transmits the packet on which header decompression isperformed, to a upper layer (e.g., an IP layer) (JS20090). During theaforementioned process, when the HCF and the EF are disabled, thereceiver recognizes the processed packet stream as an IP packet andtransmits the corresponding packet to the IP layer.

When the receiver does not receive link layer mode related informationor a corresponding system does not transmit the link layer mode relatedinformation to the receiver, the following operation is performed.

The receiver receives signaling information and/or channel information(JS20010) and selects a DP for reception and processing according tocorresponding information (JS20020). The receiver performs decoding ofthe physical layer on the selected DP to acquire a packet stream(JS20030).

The receiver checks whether the received signaling includes link layermode control related signaling (JS20040).

Since the receiver does not receive link layer mode related signaling,the receiver checks a format of the packet transmitted using physicallayer signaling, etc. (JS20100). Here, the physical layer signalinginformation may include information for identification of a type of thepacket included in a payload of the DP. When the packet transmitted fromthe physical layer is an IP packet, the receiver transmits the packet tothe IP layer without a separate process in a link layer.

When a packet transmitted from a physical layer is a packet on whichencapsulation is performed, the receiver performs a decapsulationprocess on the corresponding packet (JS20110).

The receiver checks the form of a packet included in a payload usinginformation such as a header, etc. of the link layer packet during thedecapsulation process (JS20120), and the receiver transmits thecorresponding packet to the IP layer processor when the payload is an IPpacket.

When the payload of the link layer packet is a compressed IP, thereceiver performs a decompression process on the corresponding packet(JS20130).

The receiver transmits the IP packet to an IP layer processor (JS20140).

FIG. 65 is a diagram illustrating information for identifying anencapsulation mode according to an embodiment of the present invention.

In a broadcast system, when processing in a link layer operates in oneor more modes, a procedure for determining as which mode processing inthe link layer operates (in a transmitter and/or a receiver) may beneeded. In a procedure of establishing a transmission link between thetransmitter and the receiver, the transmitter and/or the receiver mayconfirm configuration information of the link layer. This case maycorrespond to the case in which the receiver is initially set up orperforms a scan procedure for a service or a mobile receiver newlyenters an area within a transmission radius of the transmitter. Thisprocedure may be referred to as an initialization procedure or abootstrapping procedure. This procedure may be configured as a partialprocess of a procedure supported by the system without being configuredby an additional procedure. In this specification, this procedure willbe referred to as an initialization procedure.

Parameters needed in the initialization procedure may be determinedaccording to functions supported by a corresponding link layer and typesof operating modes possessed by each function. A description will begiven hereinafter of the parameters capable of determining functionsconstituting the link layer and operation modes according to thefunctions.

The above-described drawing illustrates parameters for identifying anencapsulation mode.

When a procedure for encapsulating a packet in a link layer or a upperlayer (e.g., an IP layer) can be configured, indexes are assigned torespective encapsulation modes and a proper field value may be allocatedto each index. The drawing illustrates an embodiment of a field valuemapped to each encapsulation mode. While it is assumed that a 2-bitfield value is assigned in this embodiment, the field value may beexpanded within a range permitted by the system in actualimplementation, when more supportable encapsulation modes are present.

In this embodiment, if a field of information indicating anencapsulation mode is set to ‘00’, the corresponding information mayrepresent that encapsulation in a link layer is bypasses and notperformed. If a field of information indicating an encapsulation mode isset to ‘01’, the corresponding information may represent that data isprocessed by a first encapsulation scheme in the link layer. If a fieldof information indicating an encapsulation mode is set to ‘10’, thecorresponding information may represent that data is processed by asecond encapsulation scheme in the link layer. If a field of informationindicating an encapsulation mode is set to ‘11’, the correspondinginformation may represent that data is processed by a thirdencapsulation scheme in the link layer.

FIG. 66 is a diagram illustrating information for identifying a headercompression mode according to an embodiment of the present invention.

Processing in a link layer may include a function of header compressionof an IP packet. If a few IP header compression schemes are capable ofbeing supported in the link layer, a transmitter may determine whichscheme the transmitter is to use.

Determination of a header compression mode generally accompanies anencapsulation function. Therefore, when the encapsulation mode isdisabled, the header compression mode may also be disabled. Theabove-described drawing illustrates an embodiment of a field valuemapped to each header compression mode. While it is assumed that a 3-bitfield value is assigned in this embodiment, the field value may beexpanded or shortened within a range permitted by the system in actualimplementation according to a supportable header compression mode.

In this embodiment, if a field of information indicating the headercompression mode is set to ‘000’, the corresponding information mayindicate that header compression processing for data is not performed ina link layer. If a field of information indicating the headercompression mode is set to ‘001’, the corresponding information mayindicate that header compression processing for data in the link layeruses an RoHC scheme. If a field of information indicating the headercompression mode is set to ‘010’, the corresponding information mayindicate that header compression processing for data in the link layeruses a second RoHC scheme. If a field of information indicating theheader compression mode is set to ‘011’, the corresponding informationmay indicate that header compression processing for data in the linklayer uses a third RoHC scheme. If a field of information indicating theheader compression mode is set to ‘100’ to ‘111’, the correspondinginformation may indicate that header compressing for data is reserved asa region for identifying a new header compression processing scheme fordata in the link layer.

FIG. 67 is a diagram illustrating information for identifying a packetreconfiguration mode according to an embodiment of the presentinvention.

To apply a header compression scheme to a unidirectional link such as abroadcast system, the broadcast system (transmitter and/or receiver)needs to rapidly acquire context information. The broadcast system maytransmit/receive a packet stream after a header compression procedure inan out-of-band form through reconfiguration of partial compressedpackets and/or extraction of context information. In the presentinvention, a mode for reconfiguring a packet or performing processingsuch as addition of information capable of identifying the structure ofthe packet may be referred to as a packet reconfiguration mode.

The packet reconfiguration mode may use a few schemes and the broadcastsystem may designate a corresponding scheme in an initializationprocedure of a link layer. The above-described drawing illustrates anembodiment of an index and a field value mapped to the packetreconfiguration mode. While it is assumed that a 2-bit field value isassigned in this embodiment, the field value may be expanded orshortened within a range permitted by the system in actualimplementation according to a supportable packet reconfiguration mode.

In this embodiment, if a field of information indicating the packetreconfiguration mode is set to ‘00’, corresponding information mayrepresent that reconfiguration for a packet transmitting data is notperformed in a link layer. If a field of information indicating thepacket reconfiguration mode is set to ‘01’, corresponding informationmay represent that a first reconfiguration scheme is performed for apacket transmitting data in the link layer. If a field of informationindicating the packet reconfiguration mode is set to ‘10’, correspondinginformation may represent that a second reconfiguration scheme isperformed for a packet transmitting data in the link layer. If a fieldof information indicating the packet reconfiguration mode is set to‘11’, corresponding information may represent that a thirdreconfiguration scheme is performed for a packet transmitting data inthe link layer.

FIG. 68 is a diagram illustrating a context transmission mode accordingto an embodiment of the present invention.

A transmission scheme of the above-described context information mayinclude one or more transmission modes. That is, the broadcast systemmay transmit the context information in many ways. In the broadcastsystem, a context transmission mode may be determined according to thesystem and/or a transmission path of a logical physical layer andinformation for identifying the context transmission scheme may besignaled. The above-described drawing illustrates an embodiment of anindex and a field value mapped to the context transmission mode. Whileit is assumed that a 3-bit field value is assigned in this embodiment,the field value may be expanded or shortened within a range permitted bythe system in actual implementation according to a supportable contexttransmission mode.

In this embodiment, if a field of information indicating the contexttransmission mode is set to ‘000’, corresponding field information mayrepresent that context information is transmitted as a firsttransmission mode. If a field of information indicating the contexttransmission mode is set to ‘001’, corresponding information mayrepresent that context information is transmitted as a secondtransmission mode. If a field of information indicating the contexttransmission mode is set to ‘010’, corresponding information mayrepresent that context information is transmitted as a thirdtransmission mode. If a field of information indicating the contexttransmission mode is set to ‘011’, corresponding information mayrepresent that context information is transmitted as a fourthtransmission mode. If a field of information indicating the contexttransmission mode is set to ‘100’, corresponding information mayrepresent that context information is transmitted as a fifthtransmission mode. If a field of information indicating a contexttransmission mode is set to ‘101’ to ‘111’, corresponding informationmay represent that context information is reserved to identify a newtransmission mode.

FIG. 69 is a diagram illustrating initialization information when RoHCis applied by a header compression scheme according to an embodiment ofthe present invention.

While the case in which RoHC is used for header compression has beendescribed by way of example in the present invention, similarinitialization information may be used in the broadcast system even whena header compression scheme of other types is used.

In the broadcast system, transmission of initialization informationsuitable for a corresponding compression scheme according to a headercompression mode may be needed. In this embodiment, an initializationparameter for the case in which a header compression mode is set to RoHCis described. Initialization information for RoHC may be used totransmit information about configuration of an RoHC channel which is alink between a compressor and a decompressor.

One RoHC channel may include one or more context information andinformation commonly applied to all contexts in the RoHC channel may betransmitted/received by being included in the initializationinformation. A path through which related information is transmitted byapplying RoHC may be referred to as an RoHC channel and, generally, theRoHC channel may be mapped to a link. In addition, the RoHC channel maybe generally transmitted through one DP and, in this case, the RoHCchannel may be expressed using information related to the DP.

The initialization information may include link_id information, max_cidinformation, large_cids information, num_profiles information, profiles() information, num_IP_stream information, and/or IP_address( )information.

link_id information represents an ID of a link (RoHC channel) to whichcorresponding information is applied. When the link or the RoHC channelis transmitted through one DP, link_id information may be replaced withDP id.

max_cid information represents a maximum value of a CID. max_cidinformation may be used to inform a decompressor of the maximum value ofthe CID.

large_cids information has a Boolean value and identifies whether ashort CID (0 to 15) is used or an embedded CID (0 to 16383) is used inconfiguring a CID. Therefore, a byte size expressing the CID may also bedetermined.

num_profiles information represents the number of profiles supported inan identified RoHC channel.

profiles( ) information represents a range of a protocolheader-compressed in RoHC. Since a compressor and a decompressor shouldhave the same profile in RoHC to compress and recover a stream, areceiver may acquire a parameter of RoHC used in a transmitter fromprofiles( ) information.

num_IP_stream information represents the number of IP streamstransmitted through a channel (e.g., an RoHC channel).

IP_address information represents an address of an IP stream. IP_addressinformation may represent a destination address of a filtered IP streamwhich is input to an RoHC compressor (transmitter).

FIG. 70 is a diagram illustrating information for identifying link layersignaling path configuration according to an embodiment of the presentinvention.

In the broadcast system, generally, a path through which signalinginformation is delivered is designed not to be changed. However, whenthe system is changed or while replacement between different standardsoccurs, information about configuration of a physical layer in whichlink layer signaling information rather than an IP packet is transmittedneeds to be signaled. In addition, when a mobile receiver moves betweenregions covered by transmitters having different configurations, sincepaths through which link layer signaling information is transmitted maydiffer, the case in which link layer signaling path information shouldbe transmitted may occur. The above-described drawing illustratesinformation for identifying a signaling path which is a path throughwhich the link layer signaling information is transmitted/received.Indexes may be expanded or shortened with respect to the link layersignaling information according to a signaling transmission pathconfigured in a physical layer. Separately from configuration in a linklayer, operation of a corresponding channel may conform to a procedureof the physical layer.

The above-described drawing illustrates an embodiment in whichinformation about signaling path configuration is allocated to a fieldvalue. In this specification, when multiple signaling paths aresupported, indexes may be mapped to signaling paths having greatimportance in order of small values. Signaling paths having priorityprioritized according to an index value may also be identified.

Alternatively, the broadcast system may use all signaling paths havinghigher priority than signaling paths indicated by the information aboutsignaling path configuration. For example, when a signaling pathconfiguration index value is 3, a corresponding field value may be ‘011’indicating that all of a dedicated data path, a specific signalingchannel (FIC), and a specific signaling channel (EAC), priorities ofwhich are 1, 2, and 3, are being used.

Signaling of the above scheme can reduce the amount of data thattransmits signaling information.

FIG. 71 is a diagram illustrating information about signaling pathconfiguration by a bit mapping scheme according to an embodiment of thepresent invention.

The above-described information about signaling path configuration maybe transmitted/received through definition of a bit mapping scheme. Inthis embodiment, allocation of 4 bits to the information about signalingpath configuration is considered and signaling paths corresponding torespective bits b1, b2, b3, and b4 may be mapped. If a bit value of eachposition is 0, this may indicate that a corresponding path is disabledand, if a bit value of each position is 1, this may indicate that acorresponding path is enabled. For example, if a 4-bit signaling pathconfiguration field value is ‘1100’, this may indicate that thebroadcast system is using a dedicated DP and a specific signalingchannel (FIC) in a link layer.

FIG. 72 is a flowchart illustrating a link layer initializationprocedure according to an embodiment of the present invention.

If a receiver is powered on or a mobile receiver enters a transmissionregion of a new transmitter, the receiver may perform an initializationprocedure for all or some system configurations. In this case, aninitialization procedure for a link layer may also be performed. Initialsetup of the link layer in the receiver, using the above-describedinitialization parameters may be performed as illustrated in thedrawing.

The receiver enters an initialization procedure of a link layer(JS32010).

Upon entering the initialization procedure of the link layer, thereceiver selects an encapsulation mode (JS32020). The receiver mayselect the encapsulation mode using the above-described initializationparameters in this procedure.

The receiver determines whether encapsulation is enabled (JS32030). Thereceiver may determine whether encapsulation is enabled using theabove-described initialization parameters in this procedure.

Generally, since a header compression scheme is applied after theencapsulation procedure, if an encapsulation mode is disabled, thereceiver may determine that a header compression mode is disabled(JS32080). In this case, since it is not necessary for the receiver toproceed to the initialization procedure any more, the receiver mayimmediately transmit data to another layer or transition to a dataprocessing procedure.

The receiver selects a header compression mode (JS32040) when theencapsulation mode is enabled. Upon selecting the header compressionmode, the receiver may determine a header compression scheme applied toa packet, using the above-described initialization parameter.

The receiver determines whether header compression is enabled (JS32050).If header compression is disabled, the receiver may immediately transmitdata or transition to a data processing procedure.

If header compression is enabled, the receiver selects a packet streamreconfiguration mode and/or a context transmission mode (JS32060 andJS32070) with respect to a corresponding header compression scheme. Thereceiver may select respective modes using the above-describedinformation in this procedure.

Next, the receiver may transmit data for another processing procedure orperform the data processing procedure.

FIG. 73 is a flowchart illustrating a link layer initializationprocedure according to another embodiment of the present invention.

The receiver enters an initialization procedure of a link layer(JS33010).

The receiver identifies link layer signaling path configuration(JS33020). The receiver may identify a path through which link layersignaling information is transmitted, using the above-describedinformation.

The receiver selects an encapsulation mode (JS33030). The receiver mayselect the encapsulation mode using the above-described initializationparameter.

The receiver determines whether encapsulation is enabled (JS33040). Thereceiver may determine whether encapsulation is enabled, using theabove-described initialization parameter in this procedure.

Generally, since a header compression scheme is applied after theencapsulation procedure, if an encapsulation mode is disabled, thereceiver may determine that a header compression mode is disabled(JS34100). In this case, since it is not necessary for the receiver toproceed to the initialization procedure any more, the receiver mayimmediately transmit data to another layer or transition to a dataprocessing procedure.

The receiver selects a header compression mode (JS33050) when theencapsulation mode is enabled. Upon selecting the header compressionmode, the receiver may determine a header compression scheme applied toa packet, using the above-described initialization parameter.

The receiver determines whether header compression is enabled (JS33060).If header compression is disabled, the receiver may immediately transmitdata or transition to the data processing procedure.

If header compression is enabled, the receiver selects a packet streamreconfiguration mode and/or a context transmission mode (JS33070 andJS32080) with respect to a corresponding header compression scheme. Thereceiver may select respective modes using the above-describedinformation in this procedure.

The receiver performs header compression initialization (JS33090). Thereceiver may use the above-described information in a procedure ofperforming header compression initialization. Next, the receiver maytransmit data for another processing procedure or perform the dataprocessing procedure.

FIG. 74 is a diagram illustrating a signaling format for transmitting aninitialization parameter according to an embodiment of the presentinvention.

To actually transmit the above-described initialization parameter to areceiver, the broadcast system may transmit/receive correspondinginformation in the form of a descriptor. When multiple links operated ina link layer configured in the system are present, link_id informationcapable of identifying the respective links may be assigned anddifferent parameters may be applied according to link_id information.For example, if a type of data transmitted to the link layer is an IPstream, when an IP address is not changed in the corresponding IPstream, configuration information may designate n IP address transmittedby a upper layer.

The link layer initialization descriptor for transmitting theinitialization parameter according to an embodiment of the presentinvention may include descriptor_tag information, descriptor_lengthinformation, num_link information, link_id information,encapsulation_mode information, header_compression mode information,packet_reconfiguration_mode information, context_transmission_modeinformation, max_cid information, large_cids information, num_profilesinformation, and/or profiles( ) information. A description of the aboveinformation is replaced with a description of the above-describedinformation having a similar or identical name.

FIG. 75 is a diagram illustrating a signaling format for transmitting aninitialization parameter according to another embodiment of the presentinvention.

The drawing illustrates a descriptor of another form to actuallytransmit the above-described initialization parameter to a receiver. Inthis embodiment, the above-described initial configuration informationof header compression is excluded. When an additional header compressioninitialization procedure is performed in data processing of each linklayer or an additional header compression parameter is given to a packetof each link layer, the descriptor configured in the same form as inthis embodiment may be transmitted and received.

The link layer initialization descriptor for transmitting theinitialization parameter according to another embodiment of the presentinvention may include descriptor_tag information, descriptor_lengthinformation, num_link information, link_id information,encapsulation_mode information, header_compression_mode information,packet_reconfiguration_mode information, and/orcontext_transmission_mode information. A description of the aboveinformation is replaced with a description of the above-describedinformation having a similar or identical name.

FIG. 76 is a diagram illustrating a signaling format for transmitting aninitialization parameter according to another embodiment of the presentinvention.

The drawing illustrates a descriptor of another form to actuallytransmit the above-described initialization parameter to a receiver. Inthis embodiment, a descriptor for transmitting the initializationparameter includes configuration information about a signalingtransmission path without including initial configuration information ofheader compression.

The configuration parameter about the signaling transmission path mayuse a 4-bit mapping scheme as described above. When a broadcast system(or transmitter or a receiver) for processing a broadcast signal ischanged, a link layer signaling transmission scheme or the contents oflink layer signaling may differ. In this case, if the initializationparameter is transmitted in the same form as in this embodiment, theinitialization parameter may be used even in the case of change of linklayer signaling.

The link layer initialization descriptor for transmitting theinitialization parameter according to another embodiment of the presentinvention may include descriptor_tag information, descriptor_lengthinformation, num_link information, signaling_path_configurationinformation, dedicated_DP_id information, link_id information,encapsulation_mode information, header_compression_mode information,packet_reconfiguration_mode information, and/orcontext_transmission_mode information.

When the link layer signaling information is transmitted through adedicated DP, dedicated_DP_id information is information identifying thecorresponding DP. When the dedicated DP is determined as a path fortransmitting the signaling information in signaling path configuration,DP_id may be designated to include DP_id information in the descriptorfor transmitting the initialization parameter.

A description of the above information contained in the descriptor isreplaced with a description of the above-described information having asimilar or identical name.

FIG. 77 is a diagram illustrating a receiver according to an embodimentof the present invention.

The receiver according to an embodiment of the present invention mayinclude a tuner JS21010, an ADC JS21020, a demodulator JS21030, achannel synchronizer & equalizer JS21040, a channel decoder JS21050, anL1 signaling parser JS21060, a signaling controller JS21070, a basebandcontroller JS21080, a link layer interface JS21090, an L2 signalingparser JS21100, packet header recovery JS21110, an IP packet filterJS21120, a common protocol stack processor JS21130, an SSC processingbuffer and parser JS21140, a service map database (DB) JS21150, aservice guide (SG) processor JS21160, a SG DB JS21170, an AV servicecontroller JS21180, a demultiplexer JS21190, a video decoder JS21200, avideo renderer JS21210, an audio decoder JS21220, an audio rendererJS21230, a network switch JS21240, an IP packet filter JS21250, a TCP/IPstack processor JS21260, a data service controller JS21270, and/or asystem processor JS21280.

The tuner JS21010 receives a broadcast signal.

When a broadcast signal is an analog signal, the ADC JS21020 convertsthe broadcast signal to a digital signal.

The demodulator JS21030 demodulates the broadcast signal.

The channel synchronizer & equalizer JS21040 performs channelsynchronization and/or equalization.

The channel decoder JS21050 decodes a channel in the broadcast signal.

The L1 signaling parser JS21060 parses L1 signaling information from thebroadcast signal. The L1 signaling information may correspond tophysical layer signaling information. The L1 signaling information mayinclude a transmission parameter.

The signaling controller JS21070 processes the signaling information orthe broadcast receiver transmits the signaling information to anapparatus that requires the corresponding signaling information.

The baseband controller JS21080 controls processing of the broadcastsignal in a baseband. The baseband controller JS21080 may performprocessing in the physical layer on the broadcast signal using the L1signaling information. When a connection relation between the basebandcontroller JS21080 and other apparatuses is not indicated, the basebandcontroller JS21080 may transmit the processed broadcast signal orbroadcast data to another apparatus in the receiver.

The link layer interface JS21090 accesses the link layer packet andacquires the link layer packet.

The L2 signaling parser JS21100 parses L2 signaling information. The L2signaling information may correspond to information included in theaforementioned link layer signaling packet.

When header compression is applied to a packet of a upper layer (e.g.,an IP packet) than a link layer, the packet header recovery JS21110performs header decompression on the packet. Here, the packet headerrecovery JS21110 may restore a header of the packet of the upper layerusing information for identification of whether the aforementionedheader compression is applied.

The IP packet filter JS21120 filters the IP packet transmitted to aspecific IP address and/or UDP number. The IP packet transmitted to thespecific IP address and/or UDP number may include signaling informationtransmitted through the aforementioned dedicated channel. The IP packettransmitted to the specific IP address and/or UDP number may include theaforementioned FIC, FIT, EAT, and/or emergency alert message (EAM).

The common protocol stack processor JS21130 processes data according toa protocol of each layer. For example, the common protocol stackprocessor JS21130 decodes or parses the corresponding IP packetaccording to a protocol of an IP layer and/or a upper layer than the IPlayer.

The SSC processing buffer and parser JS21140 stores or parses signalinginformation transmitted to a service signaling channel (SSC). Thespecific IP packet may be designated as an SSC and the SSC may includeinformation for acquisition of a service, attribute information includedin the service, DVB-SI information, and/or PSI/PSIP information.

The service map DB JS21150 stores a service map table. The service maptable includes attribute information about a broadcast service. Theservice map table may be included in the SSC and transmitted.

The SG processor JS21160 parses or decodes a service guide.

The SG DB JS21170 stores the service guide.

The AV service controller JS21180 performs overall control foracquisition of broadcast AV data.

The demultiplexer JS21190 divides broadcast data into video data andaudio data.

The video decoder JS21200 decodes video data.

The video renderer JS21210 generates video provided to a user using thedecoded video data.

The audio decoder JS21220 decodes audio data.

The audio renderer JS21230 generates audio provided to the user usingthe decoded audio data.

The network switch JS21240 controls an interface with other networksexcept for a broadcast network. For example, the network switch JS21240may access an IP network and may directly receive an IP packet.

The IP packet filter JS21250 filters an IP packet having a specific IPaddress and/or a UDP number.

TCP/IP stack processor JS21260 decapsulates an IP packet according to aprotocol of TCP/IP.

The data service controller JS21270 controls processing of a dataservice.

The system processor JS21280 performs overall control on the receiver.

FIG. 78 is a diagram illustrating a layer structure when a dedicatedchannel is present according to an embodiment of the present invention.

Data transmitted to a dedicated channel may not be an IP packet stream.Accordingly, a separate protocol structure from an existing IP-basedprotocol needs to be applied. Data transmitted to a dedicated channelmay be data for a specific purpose. In the dedicated channel, varioustypes of data may not coexist. In this case, the meaning ofcorresponding data may frequently become clear immediately after areceiver decodes the corresponding data in a physical layer.

In the above situation, it may not be required to process the datatransmitted to the dedicated channel according to all of theaforementioned protocol structures (for normal broadcast data). That is,in a physical layer and/or a link layer, the data transmitted to thededicated channel may be completely processed and information containedin the corresponding data can be used.

In a broadcast system, data transmitted to the dedicated channel may bedata (signaling) for signaling and the data (signaling data) forsignaling may be transmitted directly to a dedicated channel, but not inan IP stream. In this case, a receiver may more rapidly acquire the datatransmitted to the dedicated channel than data transmitted in the IPstream.

With reference to the illustrated protocol structure, a dedicatedchannel may be configured in a physical layer, and a protocol structurerelated to processing of broadcast data of this case is illustrated.

In the present invention, a part that is conformable to a generalprotocol structure may be referred to as a generic part and a protocolpart for processing a dedicated channel may be referred to as adedicated part, but the present invention is not limited thereto. Adescription of processing of broadcast data through a protocol structurein the generic part may be supplemented by the above description of thespecification.

On or more information items (dedicated information A, dedicatedinformation B, and/or dedicated information C) may be transmittedthrough a dedicated part, and corresponding information may betransmitted from outside of a link layer or generated in the link layer.The dedicated part may include one or more dedicated channels. In thededicated part, the data transmitted to the dedicated channel may beprocessed using various methods.

Dedicated information transmitted from outside to a link layer may becollected through a signaling generation and control module in the linklayer and processed in the form appropriate for each dedicated channel.A processing form of the dedicated information transmitted to thededicated channel may be referred to as a dedicated format in thepresent invention. Each dedicated format may include each dedicatedinformation item.

As necessary, data (signaling data) transmitted through the generic partmay be processed in the form of a packet of a protocol of acorresponding link layer. In this process, signaling data transmitted tothe generic part and signaling data transmitted to the dedicated partmay be multiplexed. That is, the signaling generation and control modulemay include a function for performing the aforementioned multiplexing.

When the dedicated channel is a structure that can directly processdedicated information, data in a link layer may be processed by atransparent mode; bypass mode, as described above. An operation may beperformed on some or all of dedicated channels in a transport mode, datain a dedicated part may be processed in a transparent mode, and data ina generic part may be processed in a normal mode. Alternatively, generaldata in the generic part may be processed in a transparent mode and onlysignaling data transmitted to the generic part and data in the dedicatedpart can be processed in a normal mode.

According to an embodiment of the present invention, when a dedicatedchannel is configured and dedicated information is transmitted,processing is not required according to each protocol defined in abroadcast system, and thus information (dedicated information) requiredin a receiving side can be rapidly accessed.

A description of data processing in a generic part and/or higher layersin a link layer illustrated in the drawing may be substituted with theabove description.

FIG. 79 is a diagram illustrating a layer structure when a dedicatedchannel is present according to another embodiment of the presentinvention.

According to another embodiment of the present invention, with respectto some dedicated channels among dedicated channels, a link layer may beprocessed in a transparent mode. That is, processing of data transmittedto some dedicated channels may be omitted in the link layer. Forexample, dedicated information A may not be configured in a separatededicated format and may be transmitted directly to a dedicated channel.This transmitting structure may be used when the dedicated information Ais conformable to a structure that is known in a broadcast system.Examples of the structure that is known in the broadcast system mayinclude a section table and/or a descriptor.

In the embodiment of the present invention, as a wider meaning, whendedicated information corresponds to dedicated information, up to aportion in which the corresponding signaling data is generated may beconsidered as a region of a link layer. That is, dedicated informationmay be generated in the link layer.

FIG. 80 is a diagram illustrating a layer structure when a dedicatedchannel is independently present according to an embodiment of thepresent invention.

The drawing illustrates a protocol structure for processing broadcastdata when a separate signaling generation and control module is notconfigured in a link layer. Each dedicated information item may beprocessed in the form of dedicated format and transmitted to a dedicatedchannel.

Signaling information that is not transmitted to a dedicated channel maybe processed in the form of a link layer packet and transmitted to adata pipe.

A dedicated part may have one or more protocol structure appropriate foreach dedicated channel. When the dedicated part has this structure, aseparate control module is not required in the link layer, and thus itmay be possible to configure a relatively simple system.

In the present embodiment, dedicated information A, dedicatedinformation B, and dedicated information C may be processed according todifferent protocols or the same protocol. For example, the dedicatedformat A, the dedicated format B, and the dedicated format C may havedifferent forms.

According to the present invention, an entity for generating dedicatedinformation can transmit data anytime without consideration ofscheduling of a physical layer and a link layer. As necessary, in thelink layer, data may be processed on some or all of dedicated channelsin a transparent mode or a bypass mode.

A description of data processing in a generic part and/or higher layersin a link layer illustrated in the drawing may be substituted with theabove description.

FIG. 81 is a diagram illustrating a layer structure when a dedicatedchannel is independently present according to another embodiment of thepresent invention.

When the aforementioned dedicated channel is independently present,processing in a link layer may be performed on some dedicated channelsin a transparent mode in an embodiment corresponding to a layerstructure. With reference to the drawing, dedicated information A may betransmitted directly to a dedicated channel rather than being processedin a separate format. This transmitting structure may be used when thededicated information A is conformable to a structure that is known in abroadcast system. Examples of the structure that is known in thebroadcast system may include a section table and/or a descriptor.

In the embodiment of the present invention, as a wider meaning, whendedicated information corresponds to dedicated information, up to aportion in which the corresponding signaling data is generated may beconsidered as a region of a link layer. That is, dedicated informationmay be generated in the link layer.

FIG. 82 is a diagram illustrating a layer structure when a dedicatedchannel transmits specific data according to an embodiment of thepresent invention.

Service level signaling may be bootstrapped to a dedicated channel, or afast information channel (FIC) as information for scanning a serviceand/or an emergency alert channel (EAC) including information foremergency alert may be transmitted. Data transmitted through the FIC maybe referred to as a fast information table (FIT) or a service list table(SLT) and data transmitted through the EAC may be referred to as anemergency alert table (EAT).

A description of information to be contained in a FIT and the FIT may besubstituted with the above description. The FIT may be generated andtransmitted directly by a broadcaster or a plurality of informationitems may be collected and generated in the link layer. When the FIT isgenerated and transmitted by a broadcaster, information for identifyinga corresponding broadcaster may be contained in the FIT. When aplurality of information items are collected to generate an FIT in thelink layer, information for scanning services provided by allbroadcasters may be collected to generate the FIT.

When the FIT is generated and transmitted by a broadcaster, the linklayer may be operated in a transparent mode to directly transmit the FITto an FIC. When the FIT as a combination of a plurality of informationitems owned by a transmitter is generated, generation of the FIT andconfiguration of corresponding information in the form of a table may bewithin an operating range of the link layer.

A description of information to be contained in an EAT and the EAT maybe substituted with the above description. In the case of the EAC, whenan entity (e.g., IPAWS) for managing an emergency alert messagetransmits a corresponding message to a broadcaster, an EAT related tothe corresponding message may be generated and the EAT may betransmitted through the EAC. In this case, generation of a signalingtable based on an emergency alert message may be within an operatingrange of the link layer.

The aforementioned signaling information generated in order to processIP header compression may be transmitted to a data pipe rather thanbeing transmitted through a dedicated channel. In this case, processingfor transmission of corresponding signaling information may beconformable to a protocol of a generic part and may be transmitted inthe form of a general packet (e.g., a link layer packet).

FIG. 83 is a diagram illustrating a format of (or a dedicated format) ofdata transmitted through a dedicated channel according to an embodimentof the present invention.

When dedicated information transmitted to a dedicated channel is notappropriate for transmission to a corresponding channel or requires anadditional function, the dedicated information may be encapsulated asdata, which can be processed in a physical layer, in a link layer. Inthis case, as described above, a packet structure that is conformable toa protocol of a generic part supported in a link layer may be used. Inmany cases, a function supported by a structure of a packet transmittedthrough a generic part may not be required in a dedicated channel. Inthis case, the corresponding dedicated information may be processed inthe format of the dedicated channel.

For example, in the following cases, the dedicated information may beprocessed in a dedicated format and transmitted to a dedicated channel.

1) When the size of data transmitted to a dedicated channel is notmatched with a size of dedicated information to be transmitted.

2) When dedicated information is configured in the form of data (e.g.,XML) that requires a separate parser instead of a form of a table.

3) When a version of corresponding information needs to be pre-checkedto determine whether corresponding information is processed beforecorresponding data is parsed.

4) When error needs to be detected from dedicated information.

As described above, when dedicated information needs to be processed ina dedicated format, the dedicated format may have the illustrated form.Within a range appropriate to a purpose of each dedicated channel, aheader including some of listed fields may be separately configured anda bit number allocated to a field may be changed.

According to an embodiment of the present invention, a dedicated formatmay include a length field, a data_version field, a payload_format field(or a data_format field), a stuffing_flag field, a CRC field, apayload_data_bytes( ) element, a stuffing length field, and/or astuffing_bytes field.

The length field may indicate a length of data contained in a payload.The length field may indicate the length of data in units of bytes.

The data_version field may indicate a version of information ofcorresponding data. A receiver may check whether the corresponding datais already received information or new information using the versioninformation and determine whether the corresponding information is usedusing the version information.

The data_format field may indicate a format of information contained inthe dedicated information. For example, when the data_format field has avalue of ‘000’, the value may indicate that dedicated information istransmitted in the form of a table. When the data_format field has avalue of ‘001’, the value may indicate that the dedicated information istransmitted in form of a descriptor. When the data_format field has avalue of ‘010’, the value may indicate that the dedicated information istransmitted in form of a binary format instead of a table format or adescriptor form. When the data_format field has a value of ‘011’, thevalue may indicate that the dedicated information is transmitted in formof XML.

When a dedicated channel is larger than dedicated information, astuffing byte may be added in order to match the lengths of requireddata. In this regard, the stuffing_flag field may identify whether thestuffing byte is contained.

The stuffing length field may indicate the length of the stuffing_bytesfield.

The stuffing_bytes field may be filled with a stuffing byte by as muchas the size indicated by the stuffing length field. The stuffing_bytesfield may indicate the size of a stuffing byte.

The CRC field may include information for checking error of data to betransmitted to a dedicated channel. The CRC field may be calculatedusing information (or a field) contained in dedicated information. Upondetermining that the error is detected using the CRC field, a receivermay disregard received information.

FIG. 84 is a diagram illustrating configuration information of adedicated channel for signaling information about a dedicated channelaccording to an embodiment of the present invention.

In general, determination of an operation in a transparent mode or anormal mode with respect to the aforementioned dedicated channel may bepredetermined during design of a dedicated channel and may not bechanged during management of a system. However, since a plurality oftransmitting systems and a plurality of receiving systems are present ina broadcast system, there may be a need to flexibly adjust a processingmode for a dedicated channel. In order to change or reconfigure anoperating mode of a flexible system and provide information about theoperating mode to a receiving side, signaling information may be used.The signaling information may be contained in a physical layersignaling; L1 signaling; transmitting parameter and transmitted, and maybe transmitted to one specific dedicated channel. Alternatively, thesignaling information may be contained in a portion of a descriptor or atable used in a broadcast system. That is, the information may becontained as a portion of one or more signaling information itemsdescribed in the specification.

The dedicated channel configuration information may include anum_dedicated_channel field, a dedicated_channel_id field, and/or anoperation_mode field.

The num_dedicated_channel field may indicate the number of dedicatedchannels contained in a physical layer.

The dedicated_channel_id field may correspond to an identifier foridentifying a dedicated channel. As necessary, an arbitrary identifier(ID) may be applied to a dedicated channel.

The operation_mode field may indicate a processing mode for a dedicatedchannel. For example, when the operation_mode field has a value of‘0000’, the value may indicate that the dedicated channel is processedin a normal mode. When the operation_mode field has a value of ‘1111’,the value may indicate that the dedicated channel is processed in atransparent mode or a bypass mode. ‘0001’ to ‘1110’ among values of theoperation_mode field may be reserved for future use.

Hereinafter, a method of transmitting signaling information through thelink layer according to another embodiment of the present invention isdescribed.

FIG. 85 shows a transmitter-side link layer structure and a method oftransmitting signaling information according to an embodiment of thepresent invention.

FIG. 86 shows a receiver-side link layer structure and a method ofreceiving signaling information according to an embodiment of thepresent invention.

In the embodiments of FIGS. 85 and 86, a plurality of broadcasters mayprovide services within one frequency band. Furthermore, thebroadcasters may transmit a plurality of broadcast services, and oneservice may include at least one component. On the reception side, auser may receive content in a service unit.

In order to support IP hybrid broadcasting, a session-based transportprotocol may be used. In an embodiment, the session-based transportprotocol may be the ROUTE protocol. The contents of signalinginformation transferred to each signaling path may be determineddepending on the transport structure of a corresponding protocol.Furthermore, a plurality of session-based transport protocols may beoperated.

In an embodiment, a fast information channel (FIC) and an emergencyalert channel (EAC) may be used as dedicated channels. Furthermore, abase data pipe (DP) and normal DP for transferring signaling informationmay be used. Signaling information transferred through an FIC maybecalled a fast information table (FIT), and signaling informationtransferred through an EAC maybe called an emergency alert table (EAT).If a dedicated channel has not been configured, the FIT and the EAT maybe transmitted using a common link layer signaling transmission method.In an embodiment, information about the configuration of the FIC and EACmay be transmitted through physical layer signaling. The link layer mayformat signaling information based on the characteristics of acorresponding channel. To transfer data to a specific channel of thephysical layer is performed from a logical viewpoint, and an actualoperation may comply with the characteristics of the physical layer.

An FIC or an FIT transmitted as link layer signaling information mayprovide information about the service of each broadcasting companytransmitted in a corresponding frequency and a path for receiving theservice. To this end, the link layer signaling information may includethe following information.

System parameter information: a transmitter-related parameter, abroadcasting company-related parameter that provides a service in acorresponding channel

A link layer: context information related to IP header compression andID information of a DP to which corresponding context is applied

A higher layer: an IP address and UDP port number, service and componentinformation, emergency alert information, the IP address for a packetstream and signaling information transferred in the IP layer, an UDPport number, a session ID, and information about a mapping relationbetween DPs

That is, the signaling information of the link layer may include an IPaddress, an UDP port number, and information about a mapping relationbetween PLPs.

If a plurality of broadcast services is transmitted through onefrequency band as described above, it is more efficient for a receiverto decode only a DP for a required service after checking signalinginformation without a need to decode all of DPs. Accordingly, in asystem including the transmitter configuration of FIG. 85 and thereceiver configuration of FIG. 86, such information may be obtainedusing an FIC and a base DP. The base DP may denote a DP including thesignaling information of a service layer. An operation related to thelink layer of a receiver may be performed as follows.

(1) When a user selects or changes a service to be received, thereceiver may be tuned to a corresponding frequency and may readinformation stored in a DB in relation to a corresponding channel. Theinformation stored in the DB of the receiver may be informationconfigured by reading an FIT when a channel is first scanned.

(2) After receiving the FIT and receiving information of thecorresponding channel, the receiver may update previously storedinformation. Furthermore, the receiver may obtain the transmission pathand component information of the service selected by the user or mayobtain information necessary to obtain such information. In anembodiment, if it is determined that there is no change in correspondinginformation using the version information of the FIT or a separateupdate indication method for a corresponding dedicated channel, thereceiver may omit an additional decoding or parsing operation.Information about the transmission path of the service may includeinformation, such as an IP address, an UDP port number, a session ID anda DP ID through which a service or service component is transmitted.

(3) The receiver may obtain link layer signaling information by decodinga DP included in signaling based on the information of the FIT, and maycombine the obtained link layer signaling information with signalinginformation received through a dedicated channel, if necessary. Such aprocess may be omitted if it is not necessary to receive additional linklayer signaling other than the FIT. In an embodiment, the FIT may betransmitted through a DP like a base DP other than a dedicated channel.In this case, when the base DP is decoded to receive the FIT, thereceiver may receive another piece of link layer signaling informationat the same time, may combine the received link layer signalinginformation with the FIT if necessary, and may use the combinedinformation for reception processing.

(4) The receiver may obtain transmission path information for receivinghigher layer signaling information that belongs to several packetstreams and DPs now being transmitted in a channel and that is necessaryto receive a user selection service using the FIT and the link layersignaling information. The transmission path information may include atleast one of IP address information, UDP port information, session IDinformation and DP ID information. An addressor or port numberpreviously stored in an IANA or reception system may be used as the IPaddress and UDP port number.

(5) The receiver may obtain overhead reduction information for thepacket stream of a DP corresponding to the service. The receiver mayobtain the overhead reduction information using previously stored linklayer signaling information. If DP information for receiving theselected service is received as the signaling information of a higherlayer, the receiver may obtain the DP information to be decoded byobtaining the corresponding signaling information using the same methodas DB and shared memory access. If link layer signaling and data aretransmitted through the same DP or only one DP is managed, the datatransmitted through the DP may be temporarily buffered while signalinginformation is decoded and parsed.

(6) The receiver may obtain path information on which a service isactually transmitted using higher layer signaling information for areceived service and thus may receive service data. Furthermore, thereceiver may perform de-capsulation and header recovery on a packetstream received using the overhead reduction information of a DP to bereceived and may transmit an IP packet stream to the higher layer of thereceiver.

FIG. 87 shows the transmission path of signaling information accordingto an embodiment of the present invention.

In FIG. 87, the signaling information has been classified into linklayer signaling A, link layer signaling B, signaling A, signaling B andsignaling C according to their transmission paths. Link layer signalingA may be transmitted to a dedicated channel. Signaling A-C may betransmitted in an IP packet format from a viewpoint of the link layerand may be called upper layer signaling or service layer signaling. Eachof the pieces of classified signaling information is additionallydescribed below.

1) Link layer signaling A: it indicates signaling informationtransmitted to a dedicated channel.

2) Link layer signaling B: it may be transmitted through a DP in theformat of a link layer packet. In this case, the DP may be a base DP forsignaling transmission.

3) Signaling A: it corresponds to a case where signaling data becomesthe payload of an IP/UDP packet. Values designated in the IANA or systemmay be used for an IP address and UDP port number. Signaling A issignaling information obtained using an IP address and a port number.

4) Signaling B: Signaling data is transmitted through a transportsession-based protocol and may be transmitted through a sessiondesignated in the transport session. Several transport sessions may betransmitted using the same IP addressor and port number. Accordingly,the receiver may obtain signaling information using a dedicated sessionID. In order to obtain a specific session transmitted in the samesession, the header of a packet included in a transport session-basedprotocol may be used.

5) Signaling C: it indicates a case where a separate session is notassigned to signaling data or signaling C may be transmitted along withbroadcast data. Signaling C has the same transport structure as a commonsession-based protocol. In order to obtain signaling informationtransmitted in the same session, the header of a packet included in atransport session-based protocol may be used.

FIG. 88 shows the transmission path of an FIT according to an embodimentof the present invention.

FIG. 89 shows the syntax of an FIT according to an embodiment of thepresent invention.

FIG. 88 shows an embodiment of a path through which an FIT may betransmitted in the methods of transmitting signaling information, whichhave been described in relation to FIG. 87. In an embodiment, thetransmission path of an FIT may be determined based on a channelconfigured in the physical layer and a protocol for transmitting a DP orFIT. An embodiment of each transmission path of FIG. 88 is describedbelow.

(1) If an FIT is transmitted through a dedicated channel

If a dedicated channel (e.g., an FIC) for FIT transmission has beenconfigured in the physical layer, the FIT may be transmitted through thecorresponding dedicated channel. In this case, an embodiment of thesyntax of the FIT may be defined as in a syntax A of FIG. 89. The FITmay include transmission information about the signaling of a higherlayer which is transmitted using each protocol.

(2) If an FIT is transmitted to a base DP

If a base DP is a dedicated DP that may be directly decoded withoutseparate signaling or indication, a receiver may obtain an FIT bydirectly entering or extracting the base DP when obtaining the frame ofthe physical layer. If a base DP is a DP previously not determined in asystem and has no separate signaling or indication, such information maybe transmitted as the signaling information of the physical layer. Areceiver may identify the base DP using the physical layer signalinginformation. In an embodiment, an FIT transmitted to a base DP may bedefined as in the syntax A of FIG. 89. If an FIT is transmitted througha base DP, the FIT may be encapsulated in a link layer packet formhaving a structure capable of being processed in the physical layer. Ifboth an FIT and another LLS are transmitted using a base DP, a broadcastsystem may use a separate scheme indicating that which link layer packetis a packet including an FIT through the link layer packet.

(3) If an FIT is transmitted through a normal DP

An FIT may be included in a normal DP and transmitted. In this case, abroadcast system may notify a receiver that it is a DP through whichsignaling information is transmitted using signaling information, suchas physical layer signaling (PLS). In an embodiment, an FIT transmittedto a normal DP may be defined as in the syntax A of FIG. 89. If an FITis transmitted through a normal DP, the FIT may be encapsulated in alink layer packet form having a structure capable of being processed inthe physical layer. If both an FIT and another signaling are transmittedthrough a normal DP, a broadcast system may use a separate schemeindicating that which link layer packet is a packet including an FITthrough the link layer packet.

(4) If an FIT is transmitted through a base DP in the form of an IP/UDPpacket

As in the case of (2), if a base DP is used, a link layer packet may betransmitted through the base DP, and the payload of the link layerpacket may include an IP/UDP packet. Furthermore, an FIT may be includedin the IP/UDP packet. The IP/UDP packet including the FIT may have apredefined dedicated IP address and port number. Alternatively, an IPaddress and a port number by which the FIT is transmitted may betransmitted through separate signaling. If an FIT and another signalinginformation have the same IP address and port number, table IDinformation capable of distinguishing the FIT from another signalingneeds to be included in the FIT. In this case, the FIT may be defined asin a syntax B of FIG. 89. An embodiment of the syntax of the FIT of FIG.89 includes table ID information corresponding to an FIT.

(5) If an FIT is transmitted in the form of an IP/UDP packet transmittedthrough a normal DP

As in the case of (3), an FIT may be included in an IP/UDP packetincluded in a DP through which signaling information is transmitted. Areceiver may check that a DP is a DP through which signaling istransmitted as described in (3), and an IP/UDP packet included in thepayload of a transmitted link layer packet may include the FIT.Information about the IP/UDP packet including the FIT may be determinedas described in the case of (4). The FIT may be defined as in the syntaxB of FIG. 89.

(6) If an FIT is transmitted through an EAC

An EAC is defined as a separate dedicated channel through whichemergency alert (EA) information is transmitted, but an FIT may betransmitted through an EAC for the fast reception of the FIT.Furthermore, if an additional dedicated channel is configured, the FITmay be transmitted through the dedicated channel. In such an embodiment,the FIT may be defined as in the syntax A of FIG. 89.

(7) If an FIT is transmitted in a transport session-based packet form

Signaling data may be transmitted using a transport session-basedprotocol. Furthermore, an FIT may be transmitted in the form of a packetfor the transport session-based protocol. In this case, a value, such asa session ID, may be used for the classification of a transportsession-based packet including an FIT. In this case, the FIT may bedefined as in the syntax B of FIG. 89.

FIG. 90 shows FIT information according to an embodiment of the presentinvention.

An FIT includes information about each service included in a broadcaststream and supports fast channel scan and service acquisition. An FITprovides enough information to allow the presentation of a service listthat is meaningful to a user, and supports a service selection via theup/down zapping of a channel number. An FIT includes information about alocation from which the service layer signaling of a service may beobtained. The service layer signaling may be obtained in broadcastand/or broadband. Fields included in the FIT are described below.

FIT_protocol_version: this field is an 8-bit unsigned integer andindicates the version of the structure of an FIT.

broadcast_stream_id: this field is a 16-bit unsigned integer andidentifies the entire broadcast stream.

FIT_section_number: this field is a 4-bit field and assigns a sectionnumber. An FIT may include a plurality of FIT sections.

total_FIT_section_number: this field is a 4-bit field and indicates atotal number of FIT sections including an FIT section (i.e., thegreatest value of the FIT_section_number may become totalFIT_section_number).

FIT_section_version: this field is a 4-bit field and indicates theversion number of an FIT section. The version number may be increased by1 when information carried by an FIT section is changed. When a maximumvalue is reached, FIT_section_version may return to 0.

FIT_section_length: this field is a 12-bit field and indicates thenumber of bytes of an FIT section. This field indicates the number ofbytes of the FIT, starting immediately following the FIT_section_lengthfield.

num_services: this field is an 8-bit unsigned integer and indicates thenumber of services described in an FIT instance. This field may includeservices having at least one component in each broadcast stream.

service_id: this field is a 16-bit unsigned integer and indicates an IDuniquely identifying a service within a corresponding broadcast area.

SLS_data_version: this field is an 8-bit unsigned integer that increaseswhen a service entry for the service of an FIT or a signaling table fora service carried through service layer signaling is changed. A receivermay be aware that there is a change in signaling for a specific serviceby monitoring only an FIT.

service_category: this field is a 5-bit unsigned integer and mayindicate the category of a service. The service category may be coded asin FIG. 91 below. The table of FIG. 91 may be expressed as in Table 27.FIG. 91 shows service category information according to an embodiment ofthe present invention.

TABLE 27 SERVICE CATEGORY MEANING 0x00 Service category not described ina service category field 0x01 A/V service 0x02 Audio service 0x03App-based service 0x04~0x07 Reserved for future use 0x08 Serviceguide-service guide announcement 0x09~0x1F Reserved for future use

provider_id: this field is an 8-bit unsigned integer and identifies aprovider that broadcasts a service.

short_service_name_length: this field is a 3-bit unsigned integer andindicates the number of byte pairs within the short_service_name field.If there is no short name provided for this service, the value of thisfield may be 0.

short_service_name: this field indicates the short name of a service.Each character may be encoded in UTF-8 (per UTF-8). If an odd number ofbytes are present in the short name, the second byte of the last bytepair per pair count indicated by the short_service_name_length field mayinclude 0x00.

service_status: this field is a 3-bit unsigned integer field and mayindicate the state (active/inactive, hidden/shown) of a service. The MSBmay indicate whether a service is active (set to 1) or inactive (set to0), and the LSB may indicate whether a service is hidden (set to 1) oris not hidden (set to 0).

sp_indicator: if this field is set as a 1-bit flag, it indicates whetherat least one component for meaningful presentation has been protected.If this field is set to 0, it indicates that a component necessary forthe meaningful presentation of a service is not protected.

num_service_level_descriptors: this field is a 4-bit unsigned integerfield and indicates the number of service level descriptors for acorresponding service.

service_level_descriptor( ) this field is 0 or at least one descriptorproviding additional information for a corresponding service.

num_FIT_level_descriptors: this field is a 4-bit field and indicates thenumber of the FIT-level descriptors for an FIT.

FIT_level_descriptor( ) this field is 0 or at least one descriptorproviding additional information for an FIT.

As a method for adding information necessary for an FIT, a descriptormay be added to the contents of a table. The descriptor may be definedas a service level descriptor or an FIT level descriptor depending onthe character of information included in the descriptor. The servicelevel descriptor includes additional information for a specific service.The FIT level descriptor may include additional information about all ofservices described by the FIT.

FIG. 92 shows a broadcast signaling location descriptor according to anembodiment of the present invention.

A broadcast signaling location descriptor may be included as a servicelevel descriptor. The broadcast signaling location descriptor may alsobe called a service layer signaling (SLS) location descriptor. The SLSlocation descriptor may include a bootstrap address for SLS for eachservice. A receiver may obtain SLS delivered using a broadcast methodbased on information included in an SLS location descriptor.

descriptor_tag: this field is an 8-bit unsigned integer and may identifya corresponding descriptor.

descriptor_length: this field is an 8-bit unsigned integer and indicatesa length from a field subsequent to this field to the end of acorresponding descriptor.

IP_version_flag: this field is a 1-bit indicator. This field indicatesthat an SLS_source_IP_address field and an SLS_destination_IP_addressfield have an IPv4 address if the value of this field is 0 and indicatesthat an SLS_source_IP_address field and an SLS_destination_IP_addressfield have an IPv6 address if the value of this field is 1.

SLS_source_IP_address flag: this field is a 1-bit flag and indicatesthat there is a service signaling channel source IP address for acorresponding service if the value of this field is 1 and that there isno service signaling channel source IP address for a correspondingservice if the value of this field is 0.

SLS_source_IP_address: if this field is present, it includes the sourceIP address of an SLS LCT channel for a service. If IP_version_flaginformation is set to 0, it has a 32-bit IPv4 address. IfIP_version_flag information is set to 1, it has a 128-bit IPv6 address.

SLS_destination_IP_address: This field includes the destination IPaddress of an SLS LCT channel for a service. If IP_version_flaginformation is set to 0, this field has a 32-bit IPv4 address. If theIP_version_flag information is set to 1, this field has a 128-bit IPv6address.

SLS_destination_UDP_port: this field is a 16-bit unsigned integer fieldand indicates the destination UDP port number of an SLS LCT channel fora corresponding service.

SLS_TSI: it is a 16-bit unsigned integer field and indicates thetransport session identifier (TSI) of an SLS LCT channel for acorresponding service.

SLS_PLP_ID: this field is an 8-bit unsigned integer field and indicatesthe identifier of a PLP including an SLS LCT channel for a correspondingservice. The PLP may be more robust than another PLP used by theservice.

In addition, protocol type information may be included. The protocoltype information indicates a protocol type in which SLS information istransmitted. In an embodiment, a protocol may be at least one of theROUTE and the MMT.

A base DP is a data pipe used for a specific purpose, and may includesignaling information or data common to a corresponding frequency slot.For efficient bandwidth management, a base DP may include data to bedelivered to a normal data pipe. If a dedicated channel is present, ifthe size of information to be transmitted deviates from theaccommodation ability of a corresponding channel, a base DP may functionto supplement such a problem. In general, one designated DP continues tobe used as a base DP, but for efficient DP management, one or more ofseveral data pipes may be dynamically selected using a signaling method,such as physical layer signaling or link layer signaling. A base DP mayalso be called a common DP or signaling DP.

An IP packet processing method in the link layer according to anembodiment of the present invention is described below. That is, an IPcompression method for supporting the efficient transmission of an IPpacket is described.

FIG. 93 is a view showing the structure of a Robust Header Compression(RoHC) packet and an uncompressed Internet Protocol (IP) packetaccording to an embodiment of the present invention.

An IP packet L1010 according to an embodiment of the present inventionmay include an IP Header, a User Datagram Protocol Header (UDP header),a Real time Transport Protocol Header (RTP Header), and/or a Payload.

An IP Header, a UDP Header, and an RTP Header according to an embodimentof the present invention may have a total length of about 40 bytes.

An RoHC Packet L1020 according to an embodiment of the present inventionmay include an RoHC Header and/or a Payload.

An RoHC Header according to an embodiment of the present invention isone obtained by compressing the headers of the IP packet. The RoHCHeader may have a length of about 1 byte.

According to an embodiment of the present invention, RoHC may indicatethe total headers as one context ID. RoHC may perform compression in ascheme in which the total headers are transported at the beginning oftransport and unchanged portions are omitted excluding context ID andmain information in the middle of transport.

According to an embodiment of the present invention, IP version, IPsource address, IP destination address, IP fragment flag, UDP sourceport, UDP destination port, etc. may be almost unchanged at the time ofIP streaming. Almost unchanged fields during streaming like theabove-described fields may be named static fields. RoHC according to anembodiment of the present invention may not further transport suchstatic fields for a while after transporting the static fields once. Anembodiment of the present invention may name a state in which the staticfields are not further transported for a while after transporting thestatic fields once an Initialization Refresh (IR) state and name apacket transporting the static fields an IR packet. In addition,according to an embodiment of the present invention, fields which arechanged at any time but are maintained for a predetermined time may benamed dynamic fields. An embodiment of the present invention may furthertransport the above-described dynamic fields. According to an embodimentof the present invention, a packet transporting the dynamic fields maybe named an IR-DYN packet. According to an embodiment of the presentinvention, the IR packet and the IR-DYN packet may have a similar sizeto a conventional header since the IR packet and the IR-DYN packetcontain all information of the conventional header.

According to an embodiment of the present invention, a method ofcompressing a header portion of the IP packet to reduce overhead oftransported Internet Protocol (IP) packet data may be used. According toan embodiment of the present invention, an RoHC scheme, which is one ofthe IP packet header compression schemes, may be used and the RoHCscheme may secure reliability in a wireless section. The RoHC scheme maybe used in a broadcasting system, such as Digital VideoBroadcasting—Next Generation Handheld (DVB-NGH) and a mobilecommunication system, such as Long Term Evolution (LTE). The RoHC schememay be used for a UDP and/or RTP packet although the RoHC scheme is ascheme for compressing and transporting the header of the IP packet.

According to an embodiment of the present invention, RoHC may indicatethe total headers as one context ID. RoHC may perform compression in ascheme in which the total headers are transported at the beginning oftransport and unchanged portions are omitted excluding context ID andmain information in the middle of transport. In a case in which theabove-described RoHC scheme is applied to a broadcasting system, abroadcast receiver may not know when to receive an IP stream and ageneral receiver which does not know all header information may notrecognize a corresponding IP packet. An embodiment of the presentinvention may solve the above-described problem using signaling used inthe broadcasting system.

An embodiment of the present invention may provide an IP headercompression method for supporting sufficient transport of an IP packetin a next generation digital broadcasting system.

According to another embodiment of the present invention, the RoHCscheme may be applied to a packet of a FLUTE-based protocol. In order toapply the RoHC scheme to a FLUTE/ALC/LCT packet according to anembodiment of the present invention, a packet header may be classifiedinto static fields, dynamic fields, and inferable fields. In theFLUTE/ALC/LCT packet according to an embodiment of the presentinvention, the static fields may include LCT Version Number (V),Congestion Control flag (C), Transport Session Identifier flag (S),Half-word flag(H), Congestion Control Information (CCI), TransportSession Identification (TSI), and/or Expected Residual Transmission time(ERT). LCT Version Number (V) may be a 4-bit field indicating versionnumber of an LCT protocol. This field may be fixed to 1. CongestionControl flag (C) may be a 2-bit field indicating the size of CongestionControl. This field may have a size of 32, 64, 96, or 128 bits accordingto a value. Transport Session Identifier flag (S) may be a 1-bit field,which may be a variable indicating the size of TSI. This field may havea size of 32*S+16*H. Half-word flag (H) may be a 1-bit field, which maybe a common variable indicating the size of TSI and TOI. CongestionControl Information (CCI) may have a size of 32, 64, 96, or 128 bits.This field may be a value used for a receiver to Congestion Control apacket in a transported session. This field may include the number oflayers, the number of logical channels, and sequence numbers. This fieldmay be used to refer to throughput of an available bandwidth in a pathbetween a transmitter and the receiver. Transport Session Identification(TSI) may have a size of 16, 32, or 48 bits. This field may indicate anidentifier identifying a session from a specific transmitter. ExpectedResidual Transmission time (ERT) is a 0 or 32-bit field indicating atime during which reception is effective. In the FLUTE/ALC/LCT packetaccording to an embodiment of the present invention, the dynamic fieldsmay include Transport Object Identifier flag (O), Close Session flag(A), Close Object flag (B), LCT header length (HDR_LEN), CodePoint (CP),Sender Current Time (SCT), and/or Source Block Number(SBN). TransportObject Identifier flag (O) may be a 2-bit field, which may be a variableindicating the size of TOI. This field may have a size of 32*O+16*H.Close Session flag (A) may be a 1-bit field. This field may be generallyset to 0. This field may be set to 1 when transport of a session packetis completed. Close Object flag (B) may be a 1-bit field. This field maybe generally set to 0. This field may be set to 1 when transport of adata (Object) packet is completed. LCT header length (HDR_LEN) may be an8-bit field. This field may express a header of LCT as 32 bits.CodePoint (CP) may be an 8-bit field indicating data type. SenderCurrent Time (SCT) may be a 0 or 32-bit field indicating a time duringwhich the transmitter transports data to the receiver. Source BlockNumber (SBN) may be a 32-bit field. This field may identify a Sourceblock of an Encoding Symbol in a generated Payload. In the FLUTE/ALC/LCTpacket according to an embodiment of the present invention, theinferable fields may include Transport Object Identification (TOI), FECPayload ID, Encoding Symbol ID (ESI), and/or Encoding Symbol(s).Transport Object Identification (TOI) may be a field having 16, 32, 48,64, 80, 96, or 112 bits indicating an identifier identifying data(Object) from the receiver. The length and format of FEC Payload ID maybe set by FEC Encoding ID. This field may be included in an FEC buildingblock. Encoding Symbol ID (ESI) may be a 32-bit field identifying aspecial Encoding Symbol generated from a Source Block in a Payload.Encoding Symbol(s) may be divided data from which the receiver reformsdata and have a variable size based on a divided size.

FIG. 94 is a view showing a concept of an RoHC packet stream accordingto an embodiment of the present invention.

As shown in this figure, static fields transported while being includedin an IR packet and dynamic fields transported while being included inan IR-DYN packet may be transported only when needed. Other packets maybe transported in the form of a header compressed packet including onlyabout 1 to 2 bytes information.

According to an embodiment of the present invention, it is possible toreduce a header of 30 bytes or more per packet through theabove-described concept of the RoHC packet stream. The header compressedpacket may be classified into type 0, type 1, and type 2 according tothe form of a compressed header. Use of an RoHC packet according to anembodiment of the present invention may conform to a conventionalstandard document.

FIG. 95 is a view showing a context information propagation procedureduring transport of an RoHC packet stream according to an embodiment ofthe present invention.

As shown in this figure, full context info may be included in an IRpacket and updated context info may be included in an IR-DYN packet. Inaddition, a header compressed packet excluding the IR packet and theIR-DYN packet may not include context info.

According to an embodiment of the present invention, a receiver havingno IR information may not decode an RoHC stream until receiving the nextIR packet to configure full context for unidirectional transport havingno feedback channel. That is, in this figure, in a case in which thereceiver receives an RoHC stream from a part denoted by Turn On, thereceiver may not decode the RoHC stream until receiving the next IRpacket. An embodiment of the present invention may transport IRinformation through a separate signaling channel so as to solve theabove-described problem.

According to an embodiment of the present invention, RoHC configurationinformation, initial parameter, and/or IR packet information (fullcontext information) may be needed so as to normally decode atransported RoHC packet.

According to an embodiment of the present invention, a header compressedpacket compressed using an IP header compression method may be in-bandtransported and an IR packet including a static chain containingunchanged header information and a dynamic chain for context update maybe out-of-band transported so as to reduce overhead of IP transport andto achieve efficient transport. At this time, packets received by thereceiver may be recovered in order before transport.

FIG. 96 is a view showing a transmitting and receiving system of an IPstream, to which an IP header compression scheme according to anembodiment of the present invention is applied.

According to an embodiment of the present invention, IP streams may beconfigured to enter different Data Pipes (DPs). At this time, HeaderCompression Info may be transported to a receiver through an L2signaling transport procedure and Header Compression Info may be used torecover the IP stream, to which the IP header compression scheme isapplied, received by the receiver to an original IP stream. HeaderCompression Info may be encapsulated and transported to a DP. At thistime, Header Compression Info may be transported to a normal DP or a DPfor signaling transport (Base DP) according to the structure of aphysical layer. In addition, Header Compression Info may be transportedthrough a separate signaling channel in a case in which it is supportedby the physical layer.

According to an embodiment of the present invention, IP-DP mapping infomay be transported to the receiver through the L2 signaling transportprocedure and IP-DP mapping info may be used to recover the IP streamfrom the DP received by the receiver. IP-DP mapping info may beencapsulated and transported to a DP. At this time, IP-DP mapping infomay be transported to a normal DP or a DP for signaling transport (BaseDP) according to the structure of a physical layer. In addition, IP-DPmapping info may be transported through a separate signaling channel ina case in which it is supported by the physical layer.

As shown in this figure, an IP Stream multiplexed by a compressor may bedivided into one or more IP streams by an IP Filter L4010. Each IPstream may be compressed by an IP header compression scheme L4020 andmay be transported to each DP through an encapsulation procedure L4030.At this time, an L2 Signaling Generator L4040 may generate signalinginformation including Header Compression Info and/or IP-DP mapping info.The generated signaling information may be encapsulated and transportedto a decompressor through a Base DP or may pass through a SignalingFormatting procedure L4050 and transported to the decompressor through asignaling channel L4060.

As shown in this figure, the DPs received by the decompressor may berecovered into respective IP streams by IP-DP mapping info parsed by aSignaling Parser L4070. The IP streams, having passed through aDecapsulation procedure L4080, may be recovered into the IP streambefore the IP header compression scheme is applied by Header CompressionInfo parsed by an L2 Signaling Parser L4090.

FIG. 97 is a view showing an IP overhead reduction procedure in atransmitter/receiver according to an embodiment of the presentinvention.

According to an embodiment of the present invention, when an IP streamenters an overhead reduction procedure, an RoHC Compressor L5010 mayperform header compression for the corresponding stream. An embodimentof the present invention may use an RoHC method as a header compressionalgorithm. In a Packet Stream Configuration procedure L5020, a packetstream having passed through an RoHC procedure may be reconfiguredaccording to the form of an RoHC packet. The reconfigured RoHC packetstream may be delivered to an encapsulation layer L5040 and thentransported to the receiver through a physical layer. RoHC contextinformation and/or signaling information generated in a procedure ofreconfiguring the packet stream may be made into a transportable formthrough a signaling generator L5030 and delivered to a encapsulationlayer or a signaling module L5050 according to the form of transport.

According to an embodiment of the present invention, the receiver mayreceive a stream for service data and signaling data delivered through asignaling channel or a separate DP. A Signaling Parser L5060 may receivesignaling data to parse RoHC context information and/or signalinginformation and deliver the parsed information to a Packet StreamRecovery procedure L5070. In the Packet Stream Recovery procedure L5070,the receiver may recover the packet stream reconfigured by thecompressor into a form in which an RoHC decompressor L5080 candecompress the packet stream using RoHC context information and/orsignaling information included in the signaling data. The RoHCDecompressor L5080 may convert the recovered RoHC packet stream into anIP stream. The converted IP stream may be delivered to an upper layerthrough an IP layer.

FIG. 98 is a view showing a procedure of reconfiguring an RoHC packet toconfigure a new packet stream according to an embodiment of the presentinvention.

The present invention may include three configuration modes.

According to a first configuration mode (Configuration Mode #1) L6010,which is an embodiment of the present invention, the first configurationmode may extract a static chain and a dynamic chain from an IR packetand convert the remainder of the corresponding packet into a generalheader compressed packet. The first configuration mode may extract adynamic chain from an IR-DYN packet and convert the remainder of thecorresponding packet into a general header compressed packet. The firstconfiguration mode may transport the general header compressed packetwithout any change.

According to a second configuration mode (Configuration Mode #2) L6020,which is another embodiment of the present invention, the secondconfiguration mode may extract only a static chain from an IR packet andconvert the remainder of the corresponding packet into a general headercompressed packet. The second configuration mode may extract a dynamicchain from an IR-DYN packet and convert the remainder of thecorresponding packet into a general header compressed packet. The secondconfiguration mode may transport the general header compressed packetwithout any change.

According to a third configuration mode (Configuration Mode #3) L6030,which is another embodiment of the present invention, the thirdconfiguration mode may extract a static chain from an IR packet andconvert the remainder of the corresponding packet into an IR-DYN packet.The third configuration mode may transport the IR-DYN packet without anychange and transport a general header compressed packet without anychange.

FIG. 99 is a view showing a procedure of converting an IR packet into ageneral header compressed packet in a procedure of reconfiguring an RoHCpacket to configure a new packet stream according to an embodiment ofthe present invention.

An IR packet L7010 according to an embodiment of the present inventionmay include packet type, context ID, Profile, CRC, Static Chain, DynamicChain, and/or Payload. Packet type may indicate type of thecorresponding IR packet. For example, in this figure, the packet type ofthe IR packet may indicate 1111110D and the last D may indicate whethera dynamic chain is included in the corresponding packet. Context ID mayuse 8 bits or more bits. Context ID may identify a channel through whichthe corresponding packet is transported. Context ID may be named acontext identifier (CID). When a compressor sends a packet having anuncompressed full header while a specific CID is added thereto first andsends subsequent packets while omitting header fields having static,dynamic, or inferred properties as the same CID, a decompressor mayrecover all RTP headers by adding the omitted field to the compressionheader received after the second packet with reference to initiallystored header field information based on the CID. Profile may indicate aprofile of the IR packet identified by the packet type. CRC may indicatea CRC code for error check. Static Chain may indicate information whichis not almost changed during streaming. For example, IP version, IPsource address, IP destination address, IP fragment flag, UDP sourceport, UDP destination port, etc. may be included in the static chainduring IP streaming. Dynamic Chain may indicate information which ischanged at any time but is maintained for a predetermined time. Payloadmay include data to be transported.

A general header compressed packet L7020 according to an embodiment ofthe present invention may include Time Stamp (TS), Sequence Number (SN),CRC, and/or Payload. A general header compressed packet according to anembodiment of the present invention may correspond to a UO-1 packetcorresponding to packet type 1. Time Stamp (TS) may indicate time stampinformation for time synchronization. Sequence Number (SN) may indicateinformation indicating sequence of packets. CRC may indicate a CRC codefor error check. Payload may include data to be transported.

According to an embodiment of the present invention, a static chain anda dynamic chain may be extracted from the IR packet L7010 and theextracted static chain and dynamic chain may be transported through Outof Band L7030. The Time Stamp (TS) and the Sequence Number (SN) includedin the general header compressed packet L7020 may be re-encoded usinginformation of the dynamic chain included in the IR packet L7010. TheCRC included in the general header compressed packet L7020 may bere-calculated separately from the CRC included in the IR packet L7010.

FIG. 100 is a view showing a procedure of converting an IR-DYN packetinto a general header compressed packet in a procedure of reconfiguringan RoHC packet to configure a new packet stream according to anembodiment of the present invention.

An IR-DYN packet L8010 according to an embodiment of the presentinvention may include packet type, context ID, Profile, CRC, DynamicChain, and/or Payload. Packet type may indicate type of thecorresponding IR-DYN packet. For example, in this figure, the packettype of the IR-DYN packet may indicate 11111000. Context ID may use 8bits or more bits. Context ID may identify a channel through which thecorresponding IR-DYN packet is transported. Profile may indicate aprofile of the IR-DYN packet identified by the packet type. CRC mayindicate a CRC code for error check. Dynamic Chain may indicateinformation which is changed at any time but is maintained for apredetermined time. Payload may include data to be transported.

A general header compressed packet L8020 according to an embodiment ofthe present invention may include Time Stamp (TS), Sequence Number (SN),CRC, and/or Payload, which were previously described.

According to an embodiment of the present invention, a dynamic chain maybe extracted from the IR-DYN packet L8010 and the extracted dynamicchain may be transported through Out of Band L8030. The Time Stamp (TS)and the Sequence Number (SN) included in the general header compressedpacket L8020 may be re-encoded using information of the dynamic chainincluded in the IR-DYN packet L8010. The CRC included in the generalheader compressed packet L8020 may be re-calculated separately from theCRC included in the IR-DYN packet L8010.

FIG. 101 is a view showing a procedure of converting an IR packet intoan IR-DYN packet in a procedure of reconfiguring an RoHC packet toconfigure a new packet stream according to an embodiment of the presentinvention.

An IR packet L9010 and an IR-DYN packet L9020 according to an embodimentof the present invention were previously described in detail.

According to an embodiment of the present invention, packet type of theIR packet L9010 may be changed into a packet type value corresponding tothe IR-DYN packet L9020. A static chain may be extracted from the IRpacket L9010 and the extracted static chain may be transported throughOut of Band L9030. The remaining fields included in the IR packet L9010excluding the packet type and the static chain may be identically usedin the IR-DYN packet L9020.

According to an embodiment of the present invention, encoding andcalculation methods related to fields used in a procedure ofreconfiguring an RoHC packet to configure a new packet stream mayconform to a related standard document or other methods may be applied.

FIG. 102 is a view showing a configuration and recovery procedure of anRoHC packet stream in a first configuration mode (Configuration Mode #1)according to an embodiment of the present invention.

A configuration procedure of an RoHC packet stream in a transmitteraccording to an embodiment of the present invention is as follows.

A transmitter according to an embodiment of the present invention maydetect an IR packet and an IR-DYN packet from an RoHC packet streamL10010 based on RoHC header information. Next, the transmitter maygenerate a general header compressed packet using sequence numberincluded in the IR and IR-DYN packets. The general header compressedpacket may be arbitrarily generated since the general header compressedpacket includes Sequence Number (SN) information irrespective of whichtype the general header compressed packet has. SN may correspond toinformation basically present in RTP. For UDP, the transmitter mayarbitrarily generate and use SN. Next, the transmitter may replace thecorresponding IR or IR-DYN packet with the generated general headercompressed packet. The transmitter may extract a static chain and adynamic chain from the IR packet and extract a dynamic chain from theIR-DYN packet. The extracted static chain and dynamic chain may betransported through Out of Band L10030. For all RoHC packet streams, thetransmitter may replace headers of the IR and IR-DYN packets with aheader of the general header compressed packet through the sameprocedure as the above-described procedure and extract a static chainand/or a dynamic chain. A reconfigured packet stream L10020 may betransported through a data pipe and the extracted static chain anddynamic chain may be transported through Out of Band L10030.

A recovery procedure of an RoHC packet stream in a receiver according toan embodiment of the present invention is as follows.

A receiver according to an embodiment of the present invention mayselect a data pipe of a stream to be received using signalinginformation. Next, the receiver may receive a packet stream to bereceived, transported through the data pipe (Received Packet Stream,L10040), and detect a static chain and a dynamic chain corresponding tothe packet stream to be received. The static chain and/or the dynamicchain may be received through Out of Band (Out of Band Reception,L10050). Next, the receiver may detect a general header compressedpacket having the same SN as the above-described static chain or dynamicchain from the pack stream transported through the data pipe using SN ofthe extracted static chain and dynamic chain. Next, the receiver maycombine the detected general header compressed packet with the staticchain and/or the dynamic chain to configure an IR and/or IR-DYN packet.The configured IR and/or IR-DYN packet may be transported to an RoHCdecompressor. In addition, the receiver may configure an RoHC packetstream L10060 including an IR packet, an IR-DYN packet, and/or a generalheader compressed packet. The configured RoHC packet stream may betransported to the RoHC decompressor. A receiver according to anembodiment of the present invention may use static chain, dynamic chain,and SN and/or Context ID of an IR packet and an IR-DYN packet to recoveran RoHC packet stream.

FIG. 103 is a view showing a configuration and recovery procedure of anRoHC packet stream in a second configuration mode (Configuration Mode#2) according to an embodiment of the present invention.

A configuration procedure of an RoHC packet stream in a transmitteraccording to an embodiment of the present invention is as follows.

A transmitter according to an embodiment of the present invention maydetect an IR packet and an IR-DYN packet from an RoHC packet streamL11010 based on RoHC header information. Next, the transmitter maygenerate a general header compressed packet using sequence numberincluded in the IR and IR-DYN packets. The general header compressedpacket may be arbitrarily generated since the general header compressedpacket includes Sequence Number (SN) information irrespective of whichtype the general header compressed packet has. SN may correspond toinformation basically present in RTP. For UDP, the transmitter mayarbitrarily generate and use SN. Next, the transmitter may replace thecorresponding IR or IR-DYN packet with the generated general headercompressed packet. The transmitter may extract a static chain from theIR packet and extract a dynamic chain from the IR-DYN packet. Theextracted static chain and dynamic chain may be transported through Outof Band L11030. For all RoHC packet streams, the transmitter may replaceheaders of the IR and IR-DYN packets with a header of the general headercompressed packet through the same procedure as the above-describedprocedure and extract a static chain and/or a dynamic chain. Areconfigured packet stream L11020 may be transported through a data pipeand the extracted static chain and dynamic chain may be transportedthrough Out of Band L11030.

A recovery procedure of an RoHC packet stream in a receiver according toan embodiment of the present invention is as follows.

A receiver according to an embodiment of the present invention mayselect a data pipe of a stream to be received using signalinginformation. Next, the receiver may receive a packet stream to bereceived, transported through the data pipe (Received Packet Stream,L11040), and detect a static chain and a dynamic chain corresponding tothe packet stream to be received. The static chain and/or the dynamicchain may be received through Out of Band (Out of Band Reception,L11050). Next, the receiver may detect a general header compressedpacket having the same SN as the above-described static chain or dynamicchain from the pack stream transported through the data pipe using SN ofthe extracted static chain and dynamic chain. Next, the receiver maycombine the detected general header compressed packet with the staticchain and/or the dynamic chain to configure an IR and/or IR-DYN packet.The configured IR and/or IR-DYN packet may be transported to an RoHCdecompressor. In addition, the receiver may configure an RoHC packetstream L11060 including an IR packet, an IR-DYN packet, and/or a generalheader compressed packet. The configured RoHC packet stream may betransported to the RoHC decompressor. A receiver according to anembodiment of the present invention may use static chain, dynamic chain,and SN and/or Context ID of an IR packet and an IR-DYN packet to recoveran RoHC packet stream.

FIG. 104 is a view showing a configuration and recovery procedure of anRoHC packet stream in a third configuration mode (Configuration Mode #3)according to an embodiment of the present invention.

A configuration procedure of an RoHC packet stream in a transmitteraccording to an embodiment of the present invention is as follows.

A transmitter according to an embodiment of the present invention maydetect an IR packet from an RoHC packet stream L12010 based on RoHCheader information. Next, the transmitter may extract a static chainfrom the IR packet and convert the IR packet into an IR-DYN packet usingthe remainder of the IR packet excluding the extracted static chain. Forall RoHC packet streams, the transmitter may replace a header of the IRpacket with a header of the IR-DYN packet through the same procedure asthe above-described procedure and extract a static chain. A reconfiguredpacket stream L12020 may be transported through a data pipe and theextracted static chain may be transported through Out of Band L12030.

A recovery procedure of an RoHC packet stream in a receiver according toan embodiment of the present invention is as follows.

A receiver according to an embodiment of the present invention mayselect a data pipe of a stream to be received using signalinginformation. Next, the receiver may receive a packet stream to bereceived, transported through the data pipe (Received Packet Stream,L12040), and detect a static chain corresponding to the packet stream tobe received. The static chain may be received through Out of Band (Outof Band Reception, L12050). Next, the receiver may detect an IR-DYNpacket from the pack stream transported through the data pipe. Next, thereceiver may combine the detected IR-DYN packet with the static chain toconfigure an IR packet. The configured IR packet may be transported toan RoHC decompressor. In addition, the receiver may configure an RoHCpacket stream L12060 including an IR packet, an IR-DYN packet, and/or ageneral header compressed packet. The configured RoHC packet stream maybe transported to the RoHC decompressor. A receiver according to anembodiment of the present invention may use static chain and SN and/orContext ID of an IR-DYN packet to recover an RoHC packet stream.

FIG. 105 is a view showing a combination of information that can bedelivered through Out of Band according to an embodiment of the presentinvention.

According to an embodiment of the present invention, a method ofdelivering a static chain and/or a dynamic chain extracted in aconfiguration procedure of an RoHC packet stream through Out of Band maymainly include a delivering method through signaling and a deliveringmethod through a data pipe, through which a parameter necessary forsystem decoding is delivered. According to an embodiment of the presentinvention, the data pipe, through which the parameter necessary for thesystem decoding is delivered, may be named Base Data Pipe (DP).

As shown in this figure, a static chain and/or a dynamic chain may bedelivered through signaling or Base DP. According to an embodiment ofthe present invention, a first transport mode (Transport Mode #1) to athird transport mode (Transport Mode #3) may be used in the firstconfiguration mode (Configuration Mode #1) or the second configurationmode (Configuration Mode #2), and a fourth transport mode (TransportMode #4) and a fifth third transport mode (Transport Mode #5) may beused in the third configuration mode (Configuration Mode #3)

According to an embodiment of the present invention, each configurationmode and transport mode may be switched and used through separatesignaling based on a situation of the system, and only one configurationmode and one transport mode may be fixed and used according to a designprocedure of the system.

As shown in this figure, in the first transport mode (Transport Mode#1), a static chain may be transported through signaling, a dynamicchain may be transported through signaling, and a general headercompressed packet may be transported through Normal Data Pipe.

As shown in this figure, in the second transport mode (Transport Mode#2), a static chain may be transported through signaling, a dynamicchain may be transported through Base Data Pipe, and a general headercompressed packet may be transported through Normal Data Pipe.

As shown in this figure, in the third transport mode (Transport Mode#3), a static chain may be transported through Base Data Pipe, a dynamicchain may be transported through Base Data Pipe, and a general headercompressed packet may be transported through Normal Data Pipe.

As shown in this figure, in the fourth transport mode (Transport Mode#4), a static chain may be transported through signaling, a dynamicchain may be transported through Normal Data Pipe, and a general headercompressed packet may be transported through Normal Data Pipe. At thistime, the dynamic chain may be transported by an IR-DYN packet.

As shown in this figure, in the fifth transport mode (Transport Mode#5), a static chain may be transported through Base Data Pipe, a dynamicchain may be transported through Normal Data Pipe, and a general headercompressed packet may be transported through Normal Data Pipe. At thistime, the dynamic chain may be transported by an IR-DYN packet.

FIG. 106 is a view showing configuration of a descriptor including astatic chain according to an embodiment of the present invention.

According to an embodiment of the present invention, a transport formatfor transport through signaling may be needed to transport a staticchain through signaling, to which a descriptor form may correspond.

A descriptor including a static chain according to an embodiment of thepresent invention may include a descriptor_tag field, adescriptor_length field, a context_id field, a context_profile field, astatic_chain_length field, and/or a static_chain( ) field.

The descriptor_tag field may indicate that this descriptor is adescriptor including a static chain.

The descriptor_length field may indicate a length of this descriptor.

The context_id field may indicate context ID for a corresponding RoHCpacket stream. The length of context ID may be decided in an initialconfiguration procedure of the system. This field may be named contextidentifier information and identify a corresponding RoHC packet streambased on a static field or a dynamic field.

The context_profile field may indicate compression protocol informationof a corresponding RoHC packet stream. That is, this field may indicateup to which protocol a header of an RoHC packet included in thecorresponding RoHC packet stream has been compressed.

The static_chain_length field may indicate the length of followingstatic chain( ) in unit of byte. In a case in which this descriptorincludes only one static chain, this field may be replaced by theabove-described descriptor length field.

The static_chain( ) field may include information for the static chain.

FIG. 107 is a view showing configuration of a descriptor including adynamic chain according to an embodiment of the present invention.

According to an embodiment of the present invention, a transport formatfor transport through signaling may be needed to transport a dynamicchain through signaling, to which a descriptor form may correspond.

A descriptor including a dynamic chain according to an embodiment of thepresent invention may include a descriptor_tag field, adescriptor_length field, a context_id field, a context_profile field, adynamic_chain_length field, and/or a dynamic_chain( ) field.

The descriptor_tag field may indicate that this descriptor is adescriptor including a dynamic chain.

The descriptor_length field may indicate a length of this descriptor.

The context_id field may indicate context ID for a corresponding RoHCpacket stream. The length of context ID may be decided in an initialconfiguration procedure of the system.

The context_profile field may indicate compression protocol informationof a corresponding RoHC packet stream.

The dynamic_chain_length field may indicate the length of followingdynamic chain( ) in unit of byte. In a case in which this descriptorincludes only one dynamic chain, this field may be replaced by theabove-described descriptor length field

The dynamic_chain( ) field may include information for the dynamicchain.

FIG. 108 is a view showing configuration of a packet format including astatic chain and a packet format including a dynamic chain according toan embodiment of the present invention.

According to an embodiment of the present invention, a transport formatfor transport in a packet form may be needed to transport a static chainand/or a dynamic chain through Base DP, to which a packet format formshown in this figure may correspond.

In order to configure a static chain and/or a dynamic chain according toan embodiment of the present invention in a packet format, a header forinforming of information about the corresponding static chain and/ordynamic chain may be added. The added header may include a Packet Typefield, a Static/Dynamic chain Indicator field, and a Payload Lengthfield. In a case in which a packet according to an embodiment of thepresent invention has a structure in which it is difficult to indicate astatic chain and/or a dynamic chain in detail, the information of theabove-described descriptor including the static chain or the dynamicchain may be included in a payload of this packet

A packet format including a static chain according to an embodiment ofthe present invention may include a Packet Type field, a Static chainIndicator field, a Payload Length field, and/or a Static Chain Bytefield.

The Packet Type field may indicate type information of this packet.

The Static chain Indicator field may indicate whether informationconstituting a payload is a static chain or a dynamic chain.

The Payload Length field may indicate the length of a payload includinga static chain.

The Static Chain Byte field may indicate information of the static chainincluded in the payload of this packet.

A packet format including a dynamic chain according to an embodiment ofthe present invention may include a Packet Type field, a Dynamic chainIndicator field, a Payload Length field, and/or a Dynamic Chain Bytefield.

The Packet Type field may indicate type information of this packet.

The Dynamic chain Indicator field may indicate whether informationconstituting a payload is a static chain or a dynamic chain.

The Payload Length field may indicate the length of a payload includinga dynamic chain.

The Dynamic Chain Byte field may indicate information of the dynamicchain included in the payload of this packet.

FIG. 109 is a diagram illustrating configuration ofROHC_init_descriptor( ) according to an embodiment of the presentinvention.

Robust header compression (RoHC) according to an embodiment of thepresent invention may be configured for a bidirectional transmissionsystem. In the bidirectional transmission system, a RoHC compressor anda RoHC decompressor according to an embodiment of the present inventionmay perform an initial set up procedure and in this procedure, transmitand receive a parameter required for the initial procedure. According toan embodiment of the present invention, the procedure for transmittingand receiving the parameter required for aforementioned initialprocedure can be referred as a negotiation procedure or aninitialization procedure. However, according to an embodiment of thepresent invention, a unidirectional system such as a broadcast systemcannot perform the aforementioned negotiation procedure and can replacethe aforementioned initialization procedure with a separate method.

According to an embodiment of the present invention, during theinitialization procedure, the RoHC compressor and the RoHC decompressormay transmit and receive the following parameters. The parameterrequired for the initial procedure according to an embodiment of thepresent invention may include MAX_CID, LARGE_CIDS, PROFILES,FEEDBACK_FOR, and/or MRRU.

MAX_CID may be used to notify the decompressor of a maximum value of acontext ID (CID).

LARGE_CIDS may indicate whether a short CID (0 to 15 (decimal number))and an embedded CID (0 to 16383 (decimal number)) are used forconfiguration of the CID. Thus, a size of a byte for representation ofthe CID may also be determined.

PROFILES may indicate a range of a protocol for header compression viaRoHC. According to an embodiment of the present invention, RoHC cancompress and restore a stream when the compressor and the decompressorhave the same profile.

FEEDBACK_FOR may correspond to an optionally used field and indicatewhether a backward channel for transmission of feedback information ispresent in a corresponding RoHC channel.

A maximum reconstructed reception unit (MRRU) may indicate a maximumsize of a segment when segmentation is used in the RoHC compressor.

According to an embodiment of the present invention, a descriptorincluding parameters may be transmitted in order to transmit a parameterrequired for the aforementioned RoHC initial procedure.

According to an embodiment of the present invention,ROHC_init_descriptor( ) may include a descriptor_tag field, adescriptor_length field, a context_id field, a context_profile field, amax_cid field, and/or a large_cid field.

The descriptor_tag field may identify whether the descriptor is adescriptor including a parameter required for a RoHC initial procedure.

The descriptor_length field may indicate a length of the descriptor.

The context_id field may indicate a CID of a corresponding RoHC packetstream.

The context_profile field may be a field including the aforementionedPROFILES parameter and indicate a range of a protocol for headercompression via RoHC.

The max_cid field may be a field including the aforementioned MAX_CIDparameter and may indicate a maximum value of a CID.

The large_cid field may be a field including the aforementionedLARGE_CIDS parameter and may indicate whether a short CID (0 to 15(decimal number)) and an embedded CID (0 to 16383 (decimal number)) areused for configuration of the CID.

According to an embodiment of the present invention,ROHC_init_descriptor( ) may include the aforementioned FEEDBACK_FORparameter and/or MRRU parameter.

FIG. 110 is a diagram illustrating configuration ofFast_Information_Chunk( ) including ROHC_init_descriptor( ) according toan embodiment of the present invention.

ROHC_init_descriptor( ) according to an embodiment of the presentinvention may be transmitted through a fast information channel (FIC).In this case, ROHC_init_descriptor( ) may be included inFast_Information_Chunk( ) and transmitted. According to an embodiment ofthe present invention, ROHC_init_descriptor( ) may be included in aservice level of Fast_Information_Chunk( ) and transmitted.

A field included in Fast_Information_Chunk( ) includingROHC_init_descriptor( ) according to an embodiment of the presentinvention has been described above.

ROHC_init_descriptor( ) according to an embodiment of the presentinvention may be changed in its term according to system configurationand changed in its size according to a system optimization situation.

Fast_Information_Chunk( ) according to an embodiment of the presentinvention may be referred to as fast information chunk.

FIG. 111 is a diagram illustrating configuration ofFast_Information_Chunk( ) including a parameter required for a RoHCinitial procedure according to an embodiment of the present invention.

The parameter required for the RoHC initial procedure according to anembodiment of the present invention may be transmitted through a fastinformation channel (FIC). In this case, the parameter required for theRoHC initial procedure may be included in Fast_Information_Chunk( ) andtransmitted. According to an embodiment of the present invention, theparameter required for the RoHC initial procedure may be included in aservice level of Fast_Information_Chunk( ) and transmitted.

A field included in Fast_Information_Chunk( ) including the parameterrequired for the RoHC initial procedure according to an embodiment ofthe present invention has been described above.

The parameter required for the RoHC initial procedure according to anembodiment of the present invention may be changed in its term accordingto system configuration and changed in its size according to a systemoptimization situation.

FIG. 112 is a diagram illustrating configuration ofFast_Information_Chunk( ) including ROHC_init_descriptor( ) according toanother embodiment of the present invention.

According to an embodiment of the present invention, when importantinformation about a component included in a broadcast service isincluded in Fast_Information_Chunk( ) and transmitted,ROHC_init_descriptor( ) may be included in a component level ofFast_Information_Chunk( ) and transmitted. That is,ROHC_init_descriptor( ) may be transmitted for each respective componentincluded in Fast_Information_Chunk( ).

A field included in Fast_Information_Chunk( ) includingROHC_init_descriptor( ) according to another embodiment of the presentinvention has been described above.

ROHC_init_descriptor( ) according to an embodiment of the presentinvention may be changed in its term according to system configurationand changed in its size according to a system optimization situation.

FIG. 113 is a diagram illustrating configuration ofFast_Information_Chunk( ) including a parameter required for a RoHCinitial procedure according to another embodiment of the presentinvention.

According to an embodiment of the present invention, when importantinformation about a component included in a broadcast service isincluded in Fast_Information_Chunk( ) and transmitted, a parameterrequired for the RoHC initial procedure may be included in a componentlevel of Fast_Information_Chunk( ) and transmitted. That is, theparameter required for the RoHC initial procedure may be transmitted oreach respective component included in Fast_Information_Chunk( ).

A field included in Fast_Information_Chunk( ) including a parameterrequired for the RoHC initial procedure according to another embodimentof the present invention has been described above.

The parameter required for the RoHC initial procedure according to anembodiment of the present invention may be changed in its term accordingto system configuration and changed in its size according to a systemoptimization situation.

FIG. 114 illustrates a configuration of a header of a packet forsignaling according to an embodiment of the present invention. Thepacket for signaling according to the present embodiment may be referredto as a link layer packet or a signaling packet. The link layer packetaccording to the present embodiment may include a link layer packetheader and a link layer packet payload. In addition, as illustrated inFIG. 114, a packet header of the link layer packet according to thepresent embodiment may include a fixed header and an extended header. Alength of the fixed header may be restricted to 1 byte. Therefore, in anembodiment of the present invention, additional signaling informationmay be transmitted through the extended header. The fixed header mayinclude a 3-bit packet type field and a 1-bit packet configuration (PC)field. FIG. 114 illustrates a relation between fields and signalingfields transmitted through the fixed header and the extended headerincluded in the link layer packet when the packet type field is set to“110.” Hereinafter, a description will be given of the signaling fieldsincluded in FIG. 114.

The fixed header and/or the extended header according to the presentembodiment may have a configuration varying with a value of the PCfield.

The PC field is a field that indicates a packet configuration. Inparticular, the PC field may indicate processing of signalinginformation (or data) which is included in the link layer packet payloadand/or the length of the extended header information according to theprocessing of signaling information (or data).

When the PC field has a value “0”, the fixed header may include a 4-bitconcatenation count field.

The concatenation count field is a field that is present when only adescriptor other than a section table is transmitted as a signal. Theconcatenation count (count) field indicates the number of descriptorsincluded in the link layer packet payload. According to the presentembodiment, descriptors, the number of which equals a value obtained byadding 1 to a value of the concatenation count (count) field, may beincluded in one link layer packet payload. Therefore, since the numberof bits allocated to the concatenation count (count) field correspondsto 3 bits, signaling may be performed such that a maximum of eightdescriptors are configured as one link layer packet.

When the PC field has a value of “1”, the fixed header may include a1-bit last segment indicator (LI) field and a 3-bit segment ID field.

The LI field may indicate whether the link layer packet includes lastsegmentation signaling data. In other words, signaling data may besegmented and transmitted. When the LI field has a value of “0”, thevalue indicates that signaling data included in a current link layerpacket does not correspond to a last segment. When the LI field has avalue of “1”, the value indicates that the signaling data included inthe current link layer packet corresponds to the last segment.

The segment ID field may indicate an ID for identification of a segmentwhen signaling data is segmented.

The extended header according to the present embodiment may have aconfiguration varying with the configuration of the fixed header.

However, as illustrated in the figure, the extended header according tothe present embodiment may include a signaling class field, aninformation type field, and a signaling format field irrespective of theconfiguration of the fixed header. The field that is included in theextended header according to an embodiment of the present invention maybe applied other layers. This may be changed by a designer.

The signaling class field according to the present embodiment mayindicate a class of signaling included in the link layer packet payload.Specifically, the packet header according to the present embodiment maybe used for one of signaling for channel scan and service acquisition,signaling for emergency alert, and signaling for header compression.When each of the signaling instances is used, the link layer packetpayload according to the present embodiment may transmit associatedsignaling information. In addition, the signaling class field accordingto the present embodiment may have a length of 3 bits, which may bechanged by a designer. Details will be described below.

The information type field according to the present embodiment may havea length of 2 bits or 3 bits, and indicate a type of signalinginformation included in the link layer packet payload. This may bechanged by a designer. Details will be described below.

The signaling format field according to the present embodiment may havea length of 3 bits, which may be changed by a designer.

As described in the foregoing, when the PC field has a value of “0”, theextended header according to the present embodiment may include thesignaling class field, the information type field, and the signalingformat field. In this case, the extended header according to the presentembodiment may include a payload length part field according to a valueof the signaling format field.

A value that indicates a whole length of the link layer packet or avalue that indicates a length of the payload of the link layer packetmay be allocated to the above-described payload length part fielddepending on system configuration.

In addition, when the PC field has a value of “1”, the extended headeraccording to the present embodiment may include a 4-bit segment sequencenumber (Seg_SN) field.

When the LI field has a value of “0”, the extended header according tothe present embodiment may include a 4-bit Seg_SN field, a 4-bit segmentlength ID field, the signaling class field, the information type field,and the signaling format field.

When the signaling data is segmented, the segment sequence number fieldindicates an order of respective segments. A head of the signaling dataincludes an index of a corresponding data table, and thus the respectivesegments segmented when a receiver receives the packet need to bealigned in order. Link layer packets having payloads segmented from onepiece of signaling data have the same segment ID and may have differentsegment sequence numbers.

The segment length ID field may indicate a length of a correspondingsegment.

When the LI field has a value of “1”, the extended header according tothe present embodiment may include a 4-bit Seg_SN field and a 12-bitlast segment length field. The Seg_SN field may indicate an order of asegment corresponding to a last segment ID, and the last segment lengthfield may indicate a length of the corresponding segment. FIG. 115 is achart that defines the signaling class field according to the presentembodiment.

A left column of the chart indicates a value of a 3-bit signaling classfield, and a right column of the chart indicates a description of a typeof signaling of a packet header indicated by a value of each signalingclass field.

Hereinafter, a description will be given of the value of each signalingclass field.

When the signaling class field has a value of “000”, signaling of thepacket payload corresponds to the signaling for channel scan and serviceacquisition. As illustrated in the figure, the description maycorrespond to “Signaling for Channel Scan and Service Acquisition.” Inthis case, the link layer packet payload may transmit signalinginformation related to channel scan and service acquisition.

When the signaling class field has a value of “001”, signaling of thepacket header corresponds to the signaling for emergency alert. Asillustrated in the figure, the description may correspond to “Signalingfor Emergency Alert.” In this case, the link layer packet payload maytransmit signaling information related to emergency alert.

When the signaling class field has a value of “010”, signaling of thepacket header corresponds to the signaling for header compression. Asillustrated in the figure, the description may correspond to “Signalingfor Header Compression.” In this case, the link layer packet payload maytransmit signaling information related to header compression.

When the signaling class field has values of “011” to “110”, the packetheader may be used for another type of signaling in the future. In thiscase, the description may correspond to “Reserved.” In this case, thelink layer packet payload according to the present embodiment maytransmit information corresponding to signaling other than a signalingclass proposed by the present invention in the future. A valuecorresponding to one of “011” to “110” may be allocated to the signalingclass field.

When the signaling class field has a value of “111”, the packet headermay be used for two or more types of the above-described signaling. Inthis case, the description may correspond to “Various.” Therefore, thelink layer packet payload according to the present embodiment maytransmit information corresponding to signaling which corresponds to twoor more signaling classes.

FIG. 114 corresponds to a case used for the signaling for headercompression. Here, the signaling class field corresponds to a value of“010.”

FIG. 116 is a chart that defines an information type.

A left column of the chart indicates a value of a 3-bit information typefield, and a right column of the chart indicates a description of a typeof information transmitted by the packet payload indicated by a value ofeach information type field.

Specifically, FIG. 116 is a chart that defines an information type whenthe signaling class field according to the present embodiment has avalue of “010.” The information type may be indicated by a length of 3bits. In addition, the information type may indicate a type of signalinginformation included in the link layer packet payload.

The description of each information type is as shown in the chart.Hereinafter, a value of the information type field will be described.

When the information type field has a value of “000”, the descriptionmay correspond to “Initialization Information.” In this case, the linklayer packet payload may include signaling information related toinitialization information.

When the information type field has a value of “001”, the descriptionmay correspond to “Configuration Parameters.” In this case, the linklayer packet payload may include signaling information related toconfiguration parameters.

When the information type field has a value of “010”, the descriptionmay correspond to “Static Chain.” In this case, the link layer packetpayload may include signaling information related to a static chain.

When the information type field has a value of “011”, the descriptionmay correspond to “Dynamic Chain.”

FIG. 117 is a diagram illustrating a structure ofPayload_for_Initialization( ) according to an embodiment of the presentinvention when an information type for header compression has a value of“000.”

The initialization information may include information about aconfiguration of an RoHC channel between a compressor and adecompressor. The RoHC channel may transmit one or more contextinformation items. All contexts transmitted by the RoHC channel mayinclude common information. The RoHC channel may include one or aplurality of DPs.

Payload_for_Initialization( ) according to the present embodiment mayinclude a num_RoHC_channels field, an RoHC_channel_id field, a max_cidfield, a large_cids field, a num_profiles field, a profiles( ) field, anum_IP_stream field, and an IP_address( ) field.

The num_RoHC_channels field may indicate the number of RoHC channels fortransmission of packets to which RoHC is applied. An RoHC channel mayinclude one or a plurality of DPs. When the RoHC channel includes oneDP, RoHC channel information may be replaced based on information of theDP. In this case, the num_RoHC_channels field may be replaced by anum_DP field.

The RoHC_channel_id field may indicate an ID of an RoHC channel fortransmission of packets to which RoHC is applied. When the RoHC channelincludes one DP, the RoHC_channel_id field may be replaced by a DP_idfield.

The max_cid field may indicate a maximum value of a CID. A value of themax_cid field may be input to the decompressor.

The large_cids field includes the above-described large_cids field, andmay indicate whether a short CID (0 to 15 (decimal number)) is used oran embedded CID (0 to 16383 (decimal number)) is used in a configurationof the CID.

The num_profiles field may include the number of profiles supportable bythe RoHC channel.

The profiles( ) field may indicate a range of a header compressionprotocol in an RoHC process according to an embodiment of the presentinvention. In the RoHC process according to the present embodiment, thecompressor may compress RoHC packets having the same profile into astream, and the decompressor may restore the RoHC packets.

The num_IP_stream field may indicate the number of IP streamstransmitted through the RoHC channel.

The IP_address field may indicate a destination address of a filtered IPstream which is input to an RoHC compressor.

FIG. 118 is a diagram illustrating a structure ofPayload_for_ROHC_configuration( ) when the information type for headercompression has a value of “001.”

Payload_for_ROHC_configuration( ) according to the present embodimentmay include a configuration parameter. The configuration parameter mayindicate a configuration of each packet and a transmission mode of acontext.

The configuration parameter according to the present embodiment maycorrespond to a field included in Payload_for_ROHC_configuration( ) Theconfiguration parameter may indicate a packet configuration of eachcontext and/or a transmission mode (transport mode) of the context. Inthis case, RoHC_channel_id may be used to identify the same context_idstransmitted through different RoHC channels.

Payload_for_ROHC_configuration( ) according to the present embodimentmay include an RoHC_channel_id field, a context_id field, apacket_configuration_mode field, a context_transmission_mode field, anda context_profile field.

The context_id field may indicate a context ID of a corresponding RoHCpacket stream. A length of the context ID may be determined in aninitial process of configuring a system. Therefore, the length may bedetermined based on a structure of Payload_for_Initialization( )according to the present embodiment.

The packet_configuration_mode field may indicate a configuration mode ofa packet stream including a corresponding context.

The context_transmission_mode field indicates a transmission mode of acorresponding context, which is identical to the above-describedtransmission mode (or transport mode).

Description of the RoHC_channel_id field and the context profile fieldincluded in Payload_for_ROHC_configuration( ) according to the presentembodiment is similar to the above description.

FIG. 119 is a diagram illustrating a structure ofPayload_for_static_chain( ) when the information type for headercompression has a value of “010.”

Payload_for_static_chain( ) according to the present embodiment mayinclude a context_id field, a context profile field, astatic_chain_length field, a static_chain( ) field, a dynamic_chain_inclfield, a dynamic_chain_length field, and a dynamic_chain_byte field.

The dynamic_chain_incl field may indicate whether information about adynamic chain is transmitted together with information about a staticchain. Description of the context_id field, the context_profile field,the static_chain_length field, the static_chain( ) field, thedynamic_chain_length field, and the dynamic_chain_byte field included inPayload_for_static_chain( ) according to the present embodiment issimilar to the above description.

FIG. 120 is a diagram illustrating a structure ofPayload_for_dynamic_chain( ) when the information type for headercompression has a value of “011.”

Payload_for_dynamic_chain( ) according to the present embodiment mayinclude a context_id field, a context profile field, adynamic_chain_length field, and a dynamic_chain_byte field.

The description of the fields included in Payload_for_dynamic_chain( )according to the present embodiment is similar to the above description.

An IP overhead reduction method according to another embodiment of thepresent invention is described. The IP overhead reduction methods usingrobust header compression (RoHC)-U mode (RFC3905) compression have beendescribed with reference to FIGS. 93 to 120. IP overhead reductionmethods using an RoHC v2 (RFC5225) mode are described below. A packetstructure according to RoHC v2 and a method of extracting contextinformation are described, and the aforementioned descriptions of FIGS.93 to 120 may be applied to other descriptions.

The RoHCv2 profile has more excellent compression efficiency androbustness than the RFC3095 profile. The RoHCv2 profile does not definethe IR-DYN packet format defined in the RFC3095 profile. Instead, theRoHCv2 profile defines a compressed header capable of performing morerobust context repairing. In the case of the RoHCv2 mode, a transmittermay process an IP packet as an IR packet, a Co_Repair packet and acompressed packet.

FIG. 121 shows the header format of an IR packet of the RoHCv2 profileaccording to an embodiment of the present invention.

FIG. 121 shows the header format of an IR packet which transfersinformation about the entire header that has not been compressed. The IRpacket header includes a static chain and a dynamic chain.

FIG. 122 shows the header format of a CO-repair packet of the RoHCv2profile according to an embodiment of the present invention.

The CO-repair packet header may be used to transmit a dynamic chain andto update context. The CO-repair format may be used to update thecontext of all of dynamic fields by conveying an uncompressed value. Theformat may be protected by 7-bit CRC.

FIG. 123 shows a compressed header format of the RoHCv2 profileaccording to an embodiment of the present invention.

A different type may be applied depending on the configuration of acompressed header. In general, a pt_0_crc3_packet having the smallestsize may be used in a broadcast system.

In a broadcast system, a link layer processor may include an RoHC moduleand an adaptation module. As described above, the RoHC module mayperform IP header compression. The adaptation module may extract contextinformation from a compressed RoHC packet and may generate signalinginformation. In this specification, if the RoHCv2 profile is used as inFIGS. 121 to 123, the operation of the adaptation module is additionallydescribed.

FIG. 124 shows a method of generating a new packet stream byreconfiguring an RoHC packet according to an embodiment of the presentinvention.

An embodiment of the present invention may include at least one of threeconfiguration modes.

If a transmitter operates in the first configuration mode “ConfigurationMode #1”, the adaptation module may extract a static chain and a dynamicchain from an IR packet and transform the remaining portion of the IRpacket into a general header-compressed packet. Furthermore, theadaptation module may extract a dynamic chain from a Co_Repair packetand transform the remaining portion of the packet into a generalheader-compressed packet. The general header-compressed packet may betransmitted without a change in the configuration.

If a transmitter operates in the second configuration mode“Configuration Mode #2”, the adaptation module may extract a staticchain from an IR packet and transform the remaining portion of the IRpacket into a general header-compressed packet. Furthermore, theadaptation module may extract a dynamic chain from a Co_Repair packetand transform the remaining portion of the packet into a generalheader-compressed packet. The general header-compressed packet may betransmitted without a change in the configuration.

If a transmitter operates in the third configuration mode “ConfigurationMode #3”, the adaptation module may extract a static chain from an IRpacket and transform the remaining portion of the IR packet into aCo_Repair packet. Furthermore, the adaptation module may transmit theCo_Repair packet without a change in the configuration. The generalheader-compressed packet may be transmitted without a change in theconfiguration.

FIG. 125 shows a process of transforming an IR packet into a generalheader-compressed packet or PT_0_crc3_Packet in the process ofconfiguring a new packet stream by reconfiguring an RoHC packetaccording to an embodiment of the present invention.

An IR packet according to an embodiment of the present invention mayinclude a packet type, a context ID, a profile, CRC, a static chain, adynamic chain and/or payload. The packet type may indicate the type ofIR packet. For example, in FIG. 125, the packet type of the IR packetmay indicate 11111101. The context ID may use 8 bits and may use morebits. The context ID may identify a channel through which acorresponding packet is transmitted. The profile may indicate theprofile of an IR packet identified by a packet type. The CRC mayindicate CRC code for an error check. The static chain may indicateinformation rarely changed during streaming. For example, uponperforming IP streaming, an IP version, an IP source address, an IPdestination address, an IP fragment flag, an UDP source port, an UDPdestination port, etc. may be included in the static chain. The dynamicchain may indicate information that is frequently changed, but remainsintact for a specific time. The payload may include data to betransmitted.

A general header-compressed packet PT_0_crc3_Packet according to anembodiment of the present invention may include a master sequence number(MSB), CRC and/or payload. The general header-compressed packetaccording to an embodiment of the present invention may correspond to aPT_0_crc3_Packet. The CRC may indicate CRC code for an error check. Thepayload may include data to be transmitted.

In accordance with an embodiment of the present invention, a staticchain and a dynamic chain may be extracted from an IR packet, and theextracted static chain and dynamic chain may be transmitted out of bandtransport. The MSN included in the general header-compressed packetPT_0_crc3_Packet may re-encoded using information of the dynamic chainincluded in the IR packet. The CRC included in the generalheader-compressed packet PT_0_crc3_Packet may be calculated againseparately from the CRC included in the IR packet.

FIG. 126 is a diagram showing a process of transforming a Co_Repairpacket into a general header-compressed packet PT_0_crc3_Packet in theprocess of configuring a new packet stream by reconfiguring an RoHCpacket according to an embodiment of the present invention.

A Co_Repair packet according to an embodiment of the present inventionmay include a packet type, a context ID, a profile, CRC, a dynamic chainand/or payload. The packet type may indicate the type of Co_Repairpacket. For example, in FIG. 126, the packet type of the Co_Repairpacket may indicate 11111011. The context ID may use 8 bits and may usemore bits. The context ID may identify a channel through which acorresponding Co_Repair packet is transmitted. The profile may indicatethe profile of a Co_Repair packet identified by a packet type. The CRCmay indicate CRC code for an error check. The dynamic chain may indicateinformation that is frequently changed, but remains intact for aspecific time. The payload may include data to be transmitted.

The general header-compressed packet “PT_0_crc3_Packet” according to anembodiment of the present invention may include an MSN, CRC and payloadand have been described above.

In accordance with an embodiment of the present invention, a dynamicchain may be extracted from a Co_Repair packet. The extracted dynamicchain may be transmitted out of band transport. An MSN included in ageneral header-compressed packet PT_0_crc3_Packet may be re-encodedusing information of a dynamic chain included in an IR packet. CRCincluded in the general header-compressed packet PT_0_crc3_Packet may becalculated again separately from the CRC included in the IR packet.

FIG. 127 is a diagram showing a process of transforming an IR packetinto a Co_Repair packet in the process of configuring a new packetstream by reconfiguring an RoHC packet according to an embodiment of thepresent invention.

The IR packet and the Co_Repair packet according to an embodiment of thepresent invention have been described above.

In accordance with an embodiment of the present invention, the packettype value “11111101” of an IR packet may be changed to a packet typevalue “11111011” corresponding to a Co_Repair packet, and a static chainmay be extracted from the IR packet. The extracted static chain may betransmitted out of band transport. The remaining fields that belong tothe fields included in the IR packet and that exclude the packet type,the static chain and the CRC may be identically used in the Co_Repairpacket. The CRC of the IR packet may be calculated again into the twoCRCs “CRC-7” and “CRC-3” of the Co_Repair packet and transformed.

In this specification, in general, the header-compressed packet has beenillustrated as being PT_0_crc3_Packet, but PT_0_crc7_Packet may be used.The Co_Repair format may be used to update the context of all of thedynamic fields by conveying an uncompressed value thereof.

In accordance with an embodiment of the present invention, an encodingand calculation method related to a field used in the process ofconfiguring a new packet stream by reconfiguring an RoHC packet maycomply with contents included in a related standard and other methodsmay be applied thereto.

FIG. 128 shows a method of transmitting a broadcast signal according toan embodiment of the present invention.

A broadcast signal transmitter may encode the broadcast data of abroadcast service based on a delivery protocol (S128010). At least oneof the ROUTE protocol or the MMT protocol may be used as the deliveryprotocol.

The broadcast signal transmitter may link-layer process the broadcastdata (S128020). The link-layer processing of the broadcast signaltransmitter may include the steps of compressing the header of at leastone IP packet and encapsulating the IP packet into link layer packets ifthe broadcast data includes the IP packet.

The broadcast signal transmitter may physical-layer process thebroadcast data (S128030). The broadcast signal transmitter may generatea signal frame by physical-layer processing the link layer packets. Thesignal frame may include physical layer signaling information and atleast one PLP. The physical layer processing of the broadcast signaltransmitter has been described with reference to FIGS. 18 to 40.

In the link-layer processing of the broadcast signal transmitter, thecompression of an IP packet header has been described in detail withreference to FIGS. 93 to 127.

The step of compressing the IP packet header of the broadcast signaltransmitter may further include an RoHC processing step of reducing thesize of the IP packet header of each packet based on a robust headercompression (RoHC) scheme and an adaptation processing step ofextracting context information from RoHC-processed packets. The contextinformation may be transmitted as link layer signaling information. Acase where the RoHC scheme is RoHCv2 has been described in detail withreference to FIGS. 121 to 127.

If only the RoHC processing is performed, when the broadcast signalreceiver is turned on or a channel is changed, the broadcast signaltransmitter cannot decode an ROHC packet until the IR packet is decoded.Accordingly, the broadcast signal transmitter may extract the contextinformation and transmit it out of an IP stream in order to reduce suchdelay depending on the characteristics of a broadcast system. Thetransmission of such a stream may be called “out of band transport” asdescribed above. The broadcast signal receiver may directly decode alink layer packet with reference to the context information if itdecodes the link layer packet at a specific point of time by decodingthe context information transmitted as signaling information.

The RoHC-processed IP packet includes a the first packet including astatic chain and a dynamic chain, a second packet including a dynamicchain, and a compressed third packet. The static chain includes staticsubheader information, and the dynamic chain includes dynamic subheaderinformation. In an embodiment of the present invention, the first packetand the second packet may correspond to an IR packet and an IR-DYNpacket, respectively, or may correspond to an IR packet and a Co_RepairPacket, respectively, depending on an applied RoHC scheme. Specifically,in the case of the RoHCv2 scheme, the first packet and the second packetmay correspond to an IR packet and a Co_Repair Packet, respectively.

The adaptation processing may operate in a plurality of modes. In oneembodiment, the adaptation processing step may include converting thefirst packet into the third packet by extracting the static chain andthe dynamic chain from the first packet, and converting the secondpacket into the third packet by extracting the dynamic chain from thesecond packet. In this case, context information may include at leastone of the extracted static chain information and the extracted dynamicchain information. In another embodiment, the adaptation processing stepmay include converting the first packet into the second packet byextracting the static chain from the first packet. In this case, contextinformation may include the extracted static chain information.

FIG. 129 shows the broadcast signal transmitter and broadcast signalreceiver of a broadcast system according to an embodiment of the presentinvention.

The broadcast signal transmitter 129100 includes a broadcast dataencoder 129110, a link layer processor 129120 and a physical layerprocessor 129130. The description of the aforementioned transmissionmethod is applied to the operation of the broadcast signal transmitter.

The broadcast data encoder 129110 may encode broadcast data based on adelivery protocol. At least one of the ROUTE protocol and the MMTprotocol may be used as the delivery protocol.

The link layer processor 129120 may link-layer process the broadcastdata. If the broadcast data includes at least one IP packet, the linklayer processor 129120 may include an IP packet header compression unitfor compressing the header of the IP packet and an encapsulation unitfor encapsulating the IP packet into link layer packets.

The physical layer processor 129130 may physical-layer process thebroadcast data. The physical layer processor 129130 may generate asignal frame by physical-layer processing the link layer packets. Thesignal frame may include physical layer signaling information and atleast one PLP. The physical layer processing of the broadcast signaltransmitter has been described above with reference to FIGS. 18 to 40.

In the link-layer processing of the broadcast signal transmitter, thecompression of the IP packet header has been described above in detailwith reference to FIGS. 93 to 127.

The IP packet header compression unit of the broadcast signaltransmitter may further include an RoHC unit for reducing the size ofthe IP packet header of each packet based on a robust header compression(RoHC) scheme and an adaptation unit for extracting context informationfrom RoHC-processed packets. The context information may be transmittedas link layer signaling information. A case where the RoHC scheme isRoHCv2 has been described above in detail with reference to FIGS. 121 to127.

The RoHC-processed IP packet includes a first packet including a staticchain and a dynamic chain, a second packet including a dynamic chain,and a compressed third packet. The static chain includes staticsubheader information, and the dynamic chain includes dynamic subheaderinformation. In an embodiment of the present invention, the first packetand the second packet may correspond to an IR packet and an IR-DYNpacket, respectively, or may correspond to an IR packet and a Co_RepairPacket, respectively, depending on an applied RoHC scheme. Specifically,in the case of the RoHCv2 scheme, the first packet and the second packetmay correspond to an IR packet and a Co_Repair Packet, respectively

The adaptation unit may operate in a plurality of modes. In anembodiment, the adaptation unit may convert the first packet into thethird packet by extracting the static chain and the dynamic chain fromthe first packet and may convert the second packet into the third packetby extracting the dynamic chain from the second packet. In this case,context information may include at least one of the extracted staticchain information and the extracted dynamic chain information. Inanother embodiment, the adaptation processing step may includeconverting the first packet into the second packet by extracting thestatic chain from the first packet. In this case, context informationmay include the extracted static chain information.

The broadcast signal receiver 129200 may include a physical layer parser129230, a link layer parser 129220 and a broadcast data decoder 129210.The broadcast signal receiver may perform the inverse processing of theaforementioned method of transmitting a broadcast signal by thebroadcast signal transmitter.

The physical layer parser 129230 may extract broadcast data andsignaling information by physical-layer processing a received broadcastsignal frame.

The link layer parser 129220 may recover the broadcast data of a linklayer packet format to an IP packet. The link layer parser 129220 mayrecover a compressed IP packet header based on context information.

The broadcast data decoder 129210 may decode the broadcast data based ona transport protocol and output/provide a service/service content.

The module or unit may correspond to processors for executing continuousexecution processes stored in memory (or a storage unit). Each of thesteps described in the aforementioned embodiment may be performed byhardware/processors. Each of the modules/blocks/units described in theaforementioned embodiment may operate as hardware/processor.Furthermore, the methods proposed by the present invention may beexecuted in the form of code. The code may be written in aprocessor-readable storage medium and thus may be read by a processorprovided by an apparatus.

Although the drawings have been divided and described for convenience ofdescription, the embodiments described with reference to the drawingsmay be merged to implement a new embodiment. Furthermore, to design acomputer-readable recoding medium on which a program for executing theaforementioned embodiments has been recorded according to the needs of aperson having ordinary skill in the art falls within the scope of thepresent invention.

An apparatus and method according to embodiments of the presentinvention are not limited and applied to the apparatuses and methodsaccording to the embodiments described above, and some or all of theaforementioned embodiments may be selectively combined and configured sothat the embodiments are modified in various manners.

The method proposed by the present invention may be implemented in aprocessor-readable recording medium included in a network device, in theform of processor-readable code. The processor-readable recording mediumincludes all types of recording devices in which data readable by aprocessor is stored. The processor-readable recording medium may includeROM, RAM, CD-ROM, magnetic tapes, floppy disks, and optical data storagedevices, for example. Furthermore, the processor-readable recordingmedium may be implemented in the form of carrier waves, such astransmission through the Internet. Furthermore, the processor-readablerecording medium may be distributed to computer systems connected over anetwork, and the processor-readable code may be stored and executed in adistributed manner.

Furthermore, although some embodiments of the present invention havebeen illustrated and described above, the present invention is notlimited to the aforementioned specific embodiments, and a person havingordinary skill in the art to which this specification pertains maymodify the present invention in various ways without departing from thegist of the claims. Such modified embodiments should not be individuallyinterpreted from the technical spirit or prospect of the presentinvention.

Furthermore, in this specification, both the apparatus invention and themethod invention have been described, but the descriptions of both theinventions may be complementary applied, if necessary.

Those skilled in the art will understand that the present invention maybe changed and modified in various ways without departing from thespirit or range of the present invention. Accordingly, the presentinvention is intended to include all the changes and modificationsprovided by the appended claims and equivalents thereof.

In this specification, both the apparatus and method inventions havebeen described, and the descriptions of both the apparatus and methodinventions may be complementarily applied.

MODE FOR INVENTION

Various embodiments have been described in the best form forimplementing the present invention.

INDUSTRIAL APPLICABILITY

The present invention is used for a series of the fields for providing abroadcast signal.

It is evident to those skilled in the art will understand that thepresent invention may be changed and modified in various ways withoutdeparting from the spirit or range of the present invention.Accordingly, the present invention is intended to include all thechanges and modifications provided by the appended claims andequivalents thereof.

The invention claimed is:
 1. A method of transmitting a broadcast signalby a device in a wireless network, the method comprising: link layerprocessing Internet Protocol (IP) packets to generate a plurality oflink layer packets, the plurality of link layer packets including: linklayer packets generated by compressing headers of one or more IP packetsof the IP packets and encapsulating the IP packets; and one or more linklayer packets for link layer signaling information, the one or more linklayer packets generated by encapsulating the link layer signalinginformation; physical layer processing the plurality of link layerpackets to generate the broadcast signal including a signal frame, theplurality of link layer packets carried in multiple physical layer pipes(PLPs) of the signal frame, wherein the link layer signaling informationincludes: a PLP identifier corresponding to the link layer signalinginformation, and mode information representing a mode of contextextraction of IP packets with compressed headers in a PLP identified bythe PLP identifier, wherein the mode of context extraction is a firstmode, a second mode or a third mode, and wherein the first moderepresents no context extraction, the second mode represents thatcontext information is extracted from an IR packet in IP packets ofwhich headers are compressed, and the third mode represents that contextinformation are extracted from an IR packet and an IR-dynamic packet inIP packets of which headers are compressed; and transmitting thebroadcast signal.
 2. The method of claim 1, wherein context extractionfor a first PLP of the multiple PLPs is different from contextextraction for a second PLP of the multiple PLPs.
 3. The method of claim1, wherein the link layer signaling information further includes thecontext information for a PLP to which the context extraction applied.4. The method of claim 1, wherein the context information extracted fromthe IR packet for the second mode is static chain so that the IR packetis converted to an IR-dynamic packet.
 5. The method of claim 3, whereinthe link layer signaling information further includes at least one ofcontext id information for identifying an IP stream including IP packetsof which headers are compressed, max CID information for indicatingmaximum value of the context id or context profile information forindicating a range of protocols used to compress the IP packets.
 6. Themethod of claim 5, wherein the link mapping information is encapsulatedinto the link layer packets of the second group.
 7. The method of claim1, wherein the context information extracted from the IR packet for thethird mode is static chain and dynamic chain so that the IR packet isconverted into a compressed packet, and wherein the context informationextracted from the IR-dynamic packet for the third mode is dynamic chainso that the IR-dynamic packet is converted into a compressed packet. 8.The method of claim 1, wherein the method further comprises: generatinga link mapping information providing a list of upper layer sessionscarried in a PLP of the multiple PLPs.
 9. The method of claim 1, whereina link layer packet includes a header, the header part includes packettype information indicating a type of packet encapsulated into the linklayer packet, and wherein the type is at least one of an IPv4 packet, acompressed IP packet or a link layer packet of the second groupincluding the link layer signaling information.
 10. The method of claim9, wherein a header of the link layer packet of the second group furtherincludes signaling type information indicating a type of the link layersignaling information.
 11. The method of claim 1, wherein the IP packetsincludes broadcast service data encoded by using a delivery protocol,the delivery protocol including at least one of a real-time objectdelivery over unidirectional transport (ROUTE) protocol or an MPEG mediatransport (MNIT) protocol based on a delivery protocol.
 12. The methodof claim 1, wherein a link layer packet of the first group is carried ina PLP different from a PLP carrying a link layer packet of the secondgroup.
 13. An apparatus for transmitting a broadcast signal in awireless network, the apparatus comprising: a link layer processorconfigured to link layer process Internet Protocol (IP) packets togenerate a plurality of link layer packets, wherein the plurality oflink layer packets includes: link layer packets generated by compressingheaders of one or more IP packets of the IP packets and encapsulatingthe IP packets; and one or more link layer packets for link layersignaling information, the one or more link layer packets generated byencapsulating the link layer signaling information; a physical layerprocessor configured to physical layer process the plurality of linklayer packets to generate the broadcast signal including a signal frame,the plurality of link layer packets carried in multiple physical layerpipes (PLPs) of the signal frame, wherein the link layer signalinginformation includes: a PLP identifier corresponding to the link layersignaling information, and mode information representing a mode ofcontext extraction of IP packets with compressed headers in a PLPidentified by the PLP identifier, wherein the mode of context extractionis a first mode, a second mode or a third mode, and wherein the firstmode represents no context extraction, the second mode represents thatcontext information is extracted from an IR packet in IP packets ofwhich headers are compressed, and the third mode represents that contextinformation are extracted from an IR packet and an IR-dynamic packet inIP packets of which headers are compressed; and a transmitter configuredto transmit the broadcast signal.
 14. The apparatus of claim 13, whereincontext extraction for a first PLP of the multiple PLPs is differentfrom context extraction for a second PLP of the multiple PLPs.
 15. Theapparatus of claim 13, wherein the link layer signaling informationfurther includes the context information for a PLP to which the contextextraction applied.
 16. The apparatus of claim 13, wherein the contextinformation extracted from the IR packet for the second mode is staticchain so that the IR packet is converted to an IR-dynamic packet. 17.The apparatus of claim 13, wherein the context information extractedfrom the IR packet for the third mode is static chain and dynamic chainso that the IR packet is converted into a compressed packet, and whereinthe context information extracted from the IR-dynamic packet for thethird mode is dynamic chain so that the IR-dynamic packet is convertedinto a compressed packet.
 18. The apparatus of claim 8, wherein the linklayer processor is further configured to: generate a link mappinginformation providing a list of upper layer sessions carried in a PLP ofthe multiple PLPs.